In this Vehicle Platform Guide, you will find the top common issues of Mercedes-Benz GL550 / GLS550 (X166; 2013-2019) 4.7L Turbocharged V8, along with their fault codes, and the solutions from eEuroparts.com.
The 2013-2019 Mercedes-Benz GL550 / GLS550 (X166) 4.7L Bi-Turbocharged V8 is a full-size luxury SUV that blends muscular performance with executive-class comfort and seven-passenger practicality. Powered by a 4.7L twin-turbocharged V8 gasoline engine (M278), it produces up to 449 horsepower and 516 lb-ft (700 Nm) of torque. The engine is mated to a 7-speed 7G-TRONIC (pre-facelift) or 9-speed 9G-TRONIC (post-2016 facelift) automatic transmission and Mercedes’ 4MATIC all-wheel drive system.
Specifications
Engine and Powertrain
Engine:
4.7L Twin-Turbocharged V8
Engine Code:
M278
Horsepower:
429 hp (2013-2016 GL550) / 449 hp (2017-2019 GLS550)
Torque:
516 lb-ft @ 1,800-3,500 rpm
Fuel Type:
Premium Unleaded Gasoline
Transmission:
7-Speed (GL550) / 9-Speed Automatic (GLS550)
Fuel Economy (EPA Estimates)
City/Highway Combined:
~14-19 MPG
Vehicle Weight
Curb weight:
~ 5,258 lbs
Gross Weight:
~ 7,121 lbs
Configurations and Submodels
Body Styles:
SUV
Seating Capacity:
7 passengers
Drivetrain Options:
4MATIC All-Wheel Drive (Standard)
Top Common Issues with Mercedes-Benz GL550 / GLS550 (X166; 2013-2019) 4.7L Turbocharged V8
Brake Pad Wear Sensor
1. Brake Pad Wear Sensor Failure
Fault Codes:
C1234 and C249F indicate ABS and SBC faults-right front wheel speed signal loss and SBC pump cycle limit exceeded.
Why it happens:
Brake pad wear sensor failure typically occurs due to wire breakage from pad wear, corrosion, poor installation, or electrical interference, leading to false warnings or no alerts when pads are worn.
Symptoms:
Brake warning light stays on, even after replacing pads, due to a broken or shorted sensor wire.
No warning light when pads are worn, indicating the sensor failed to trigger the alert.
Intermittent dashboard alerts, caused by loose connections or degraded sensor wiring.
False wear alerts, where the system signals pad wear prematurely despite sufficient pad thickness.
ABS or traction control lights, in some models where sensor faults affect shared circuits.
Unusual brake pedal feel, such as inconsistent pressure, if the sensor fault coincides with pad or rotor issues.
Visible damage to sensor wiring, like fraying, corrosion, or broken clips during inspection.
Grinding noise despite no warning, suggesting the sensor failed to detect pad wear in time.
Sensor-related fault codes, such as C1234 or C1525, when scanned with a diagnostic tool.
Increased stopping distance, if the sensor failure masks worn pads and delays replacement.
C0035-C0041 codes indicate wheel speed sensor faults-signal loss, circuit issues, or tone ring damage-disrupting ABS and stability control.
Why it happens:
ABS wheel speed sensor failure typically occurs due to debris buildup, corrosion, wiring damage, or heat exposure, which disrupts signal transmission to the ABS control module.
Symptoms:
ABS warning light stays illuminated, often the first sign that the sensor isn’t sending proper signals to the control module.
Loss of anti-lock braking function, causing wheels to lock during hard braking, especially on slippery surfaces.
Traction or stability control lights activate, since these systems rely on accurate wheel speed data.
Pulsating brake pedal during normal braking, as the ABS system falsely engages due to erratic sensor readings.
Speedometer malfunction or erratic readings, particularly in older vehicles where the ABS sensor feeds speed data.
Longer stopping distances, especially in emergency braking, due to disabled ABS intervention.
Inconsistent braking or pulling to one side, if one sensor fails and the system misjudges wheel behavior.
Diagnostic trouble codes (e.g., C0035-C0041) appear when scanned, pinpointing the faulty wheel sensor.
Unusual noises during braking, such as grinding or clicking, from unnecessary ABS activation.
No ABS activation in slippery conditions, increasing the risk of skidding or loss of control.
Parts to Replace
Front 1669054002 is a genuine OEM rotational speed sensor designed for precise ABS and stability control performance on Mercedes-Benz SUVs.
Yaw Rate Sensor Part # 0065422618 The Genuine Mercedes-Benz ABS Wheel Speed Sensor, part number 0065422618, is an essential component for your Mercedes-Benz car.
Front Part # 360470 The ATE ABS Wheel Speed Sensor part number 360470 is a reliable and durable replacement part designed for Mercedes-Benz vehicles.
C1326 and C1525 indicate ABS or steering sensor faults-wheel speed signal loss or brake system initialization incomplete-affecting stability control.
Why it happens:
AIRMATIC air strut failure typically occurs due to rubber bladder degradation, seal leaks, moisture intrusion, or compressor overcompensation, often accelerated by age, heat, or road debris.
Symptoms:
Vehicle sagging on one corner or side, especially after parking overnight, due to air leakage from the strut bladder.
“AIRMATIC Visit Workshop” or suspension warning light, triggered by pressure loss or sensor faults.
Bumpy or harsh ride, as the strut loses its ability to cushion road impacts.
Frequent or noisy compressor operation, indicating the system is overworking to maintain ride height.
Uneven ride height or leaning while driving, caused by a leaking or collapsed strut.
Hissing sounds near the wheel well, often from escaping air due to bladder or seal failure.
Slow or unresponsive ride height adjustment, especially when switching between comfort and sport modes.
Visible cracks or dry rot on the rubber bellows, typically seen during visual inspection.
Increased tire wear, from improper suspension geometry due to sagging.
Vehicle stuck in lowest position, if the strut fails completely or the compressor shuts down from overload.
C156E and C1511 indicate ride height calibration and torque sensor faults-causing suspension imbalance, steering issues, and stability control loss.
Why it happens:
Air suspension compressor failure typically occurs due to overheating, moisture intrusion, air leaks, worn components, or electrical faults, often triggered by aging systems or neglected maintenance.
Symptoms:
Vehicle sits lower than normal, especially after being parked overnight, due to insufficient air pressure in the suspension system.
Compressor runs excessively or continuously, indicating it’s struggling to maintain pressure-often due to leaks or internal wear.
Slow or failed ride height adjustment, where the vehicle takes too long to lift or doesn’t lift at all.
Unusual noises from the compressor, such as grinding, whining, or clicking, suggesting internal mechanical failure.
Suspension warning light or “AIRMATIC Visit Workshop” message, triggered by system pressure faults or compressor inactivity.
One side or corner of the vehicle sagging, pointing to uneven air distribution or compressor output imbalance.
No compressor activation, where the unit fails to turn on due to electrical faults, relay failure, or motor burnout.
Burning smell or melted wiring, in severe cases where the compressor overheats or draws excessive current.
Frequent battery drain, caused by a compressor that runs too often or doesn’t shut off properly.
Hissing sounds near the compressor or air lines, indicating air leaks that force the compressor to overwork.
C1525F1 and C1526FA indicate brake initialization and left rear height sensor faults, affecting AIRMATIC calibration, ride height, and stability.
Why it happens:
Suspension shock absorber failure typically occurs due to seal wear, fluid leakage, internal valve damage, or corrosion, often accelerated by age, poor installation, or harsh driving conditions.
Symptoms:
Excessive bouncing after bumps, where the vehicle continues to oscillate instead of settling quickly, indicating worn dampening.
Nose-diving during braking, as the front end dips more than normal due to reduced resistance from the shocks.
Rear-end squatting during acceleration, caused by weak rear shocks failing to control weight transfer.
Uneven tire wear, especially cupping or scalloping, from poor road contact and uncontrolled suspension movement.
Longer stopping distances, as tires lose consistent grip due to bouncing or instability.
Poor handling and body roll, especially during cornering or lane changes, from reduced suspension control.
Steering wheel vibrations, particularly at speed or over rough surfaces, due to lack of shock absorption.
Fluid leaks on the shock body, a sign of internal seal failure and loss of hydraulic dampening.
Clunking or rattling noises, especially over bumps, from worn mounts or internal shock damage.
Headlight beam instability, where lights bounce excessively at night due to vertical body movement.
P0351-P0358 indicate ignition coil circuit faults in cylinders 1-8, causing misfires, rough idle, poor performance, and increased emissions.
Why it happens:
Ignition coil or spark plug failure typically occurs due to overheating, worn plugs increasing voltage demand, contamination, or electrical faults like poor wiring or grounding.
Symptoms:
Engine misfires, especially under load or during acceleration, due to weak or inconsistent spark.
Rough idle or stalling, caused by incomplete combustion or cylinder misfire.
Check engine light, often with codes like P0300-P0358, indicating misfire or coil circuit faults.
Hard starting or no start, particularly in cold conditions or after the engine has been sitting.
Poor fuel economy, as the ECU compensates for misfires by enriching the fuel mixture.
Loss of power or hesitation, especially when accelerating, from reduced spark energy.
Backfiring or popping sounds, due to unburned fuel igniting in the exhaust.
Strong fuel smell from exhaust, indicating incomplete combustion.
Black, sooty, or oily spark plugs, showing fouling from oil, fuel, or carbon buildup.
Visible cracks or carbon tracking on ignition coils, which can cause arcing and misfire.
Parts to Replace
Mercedes-Benz Ignition Coil 2769065400 is a genuine OEM component designed to deliver high-voltage spark to the spark plugs, ensuring efficient combustion and engine performance.
NGK Mercedes-Benz Ignition Coil 49110 is a high-performance aftermarket replacement for various Mercedes-Benz models, offering OE-level reliability and spark energy.
Hitachi Mercedes-Benz Ignition Coil IGC0183 is a high-quality aftermarket or OE-equivalent component designed for various Mercedes-Benz engines, particularly the M276 and M278 platforms.
Beru Mercedes Ignition Coil ZSE093 The Beru ZSE093 direct ignition coil is a reliable replacement part for many Mercedes-Benz models. This coil provides a strong and efficient spark that helps maintain optimal performance.
Mercedes Engine Valve Lifter 6420500080 The Genuine Mercedes-Benz Engine Camshaft Follower part number 6420500080 / 642 050 00 80 is the perfect fit for your Mercedes-Benz engine.
P0335-P0385 indicate crankshaft sensor faults-malfunction, range/performance, or signal loss-causing misfires, stalling, poor timing, and drivability issues.
Why it happens:
Crankshaft position sensor failure typically occurs due to heat damage, oil contamination, vibration, aging electronics, or wiring faults disrupting signal accuracy.
Symptoms:
Check engine light turns on, often with codes like P0335, P0336, or P0385 due to signal or circuit faults.
Hard starting or no start, especially when the ECU can’t detect crankshaft position for ignition timing.
The engine stalls intermittently, as the sensor signal cuts out while driving or idling.
Misfires or rough idle, caused by incorrect spark or fuel timing.
Poor acceleration or hesitation, from erratic timing data sent to the ECU.
Reduced fuel economy, due to inefficient combustion from mistimed injection.
The engine vibrates or runs unevenly, especially at idle or under load.
Backfiring or popping sounds, from unburned fuel igniting in the exhaust.
Foul exhaust smell or black smoke, indicating incomplete combustion.
RPM gauge behaves erratically, or fluctuates unexpectedly due to inconsistent sensor signals.
Parts to Replace
Mercedes Crankshaft Position Sensor 2769051200 The Genuine Mercedes-Benz Engine Crankshaft Position Sensor part number 2769051200 / 276 905 12 00 is a top-quality replacement part for your Mercedes-Benz vehicle.
Mercedes Engine Crankshaft Position Sensor 2769051500 The Genuine Mercedes-Benz Engine Crankshaft Position Sensor part number 2769051500 is an essential component for your Mercedes-Benz that ensures the smooth running of your vehicle’s engine.
U0428 and C1142 indicate steering angle sensor communication and brake pressure sensor faults-causing stability, ABS, and braking issues.
Why it happens:
Steering shaft failure typically occurs due to wear in universal joints, corrosion from moisture intrusion, impact damage, or misalignment, all of which compromise smooth rotational transfer between the steering wheel and rack.
Symptoms:
The steering wheel feels stiff or binds, especially during low-speed turns, due to worn or corroded universal joints.
Clunking or popping noises when turning, often from loose or damaged joints in the shaft assembly.
Excessive play or looseness in the steering wheel, where it turns slightly before the wheels respond.
Vibration through the steering wheel, particularly while turning or driving over uneven surfaces.
Steering wheel doesn’t return to center after a turn, indicating binding or misalignment in the shaft.
Inconsistent steering response, where effort required to turn varies unpredictably.
Visible rust or corrosion on the shaft or joints, especially near the firewall or underbody.
Steering column movement over bumps, suggesting worn shaft couplings or mounts.
Loose or unstable tilt adjustment, where the steering wheel won’t hold its set position.
Complete loss of steering input, in severe cases where the shaft disconnects or fails internally.
Parts to Replace
OEM Mercedes Steering Shaft - Upper 1664620013 The Genuine Mercedes-Benz Steering Shaft part number 1664620013 / 166 462 00 13 is an exceptional component that is designed to replace the old, worn-out or damaged steering shaft in your Mercedes-Benz.
Steering tie rod failure typically occurs due to wear from poor lubrication, impact damage, corrosion, or misalignment, all of which compromise steering precision and safety.
Symptoms:
Uneven tire wear, especially on the inner or outer edges, due to misalignment caused by loose or worn tie rods.
Steering wheel vibration, particularly at higher speeds or while turning, from unstable wheel tracking.
Loose or unresponsive steering, where the wheel feels disconnected or has excessive play before the wheels react.
Vehicle pulling to one side, even on a straight road, indicating misaligned front wheels.
Clunking or knocking noises when turning or driving over bumps, from worn tie rod joints or bushings.
Poor alignment retention, where the vehicle quickly goes out of alignment after adjustment.
Difficulty maintaining a straight line, requiring constant steering correction.
Visible damage or torn boots on inspection, exposing the joint to dirt and moisture.
Steering wheel off-center, even when driving straight, due to altered toe settings.
Complete steering loss, in severe cases where the tie rod separates from the knuckle or rack.
Rack and pinion below failure typically occurs due to age-related cracking, road debris damage, or improper installation, allowing dirt and moisture to enter and degrade the steering rack.
Symptoms:
Visible cracks or tears in the rubber boot, often exposing the inner tie rod or rack shaft to dirt and moisture.
Grease or fluid leakage around the boot, indicating internal contamination or seal failure.
Clunking or knocking noises when turning, caused by debris entering the rack through a torn bellow.
Steering feels loose or imprecise, due to accelerated wear on the rack from unprotected movement.
Rust or corrosion on the rack shaft, visible during inspection, from prolonged exposure to water and road salt.
Uneven or accelerated inner tire wear, if the rack begins to bind or misalign due to internal damage.
Power steering fluid leaks, in severe cases where contamination damages internal seals.
Steering wheel vibration, especially at speed or over bumps, from degraded rack support.
Whining or groaning noises during steering input, if fluid aeration occurs from internal wear.
Failed inspection or alignment issues, as torn bellows often lead to rack damage and toe misalignment.
Steering knuckle failure typically occurs due to impact damage from potholes or curbs, corrosion, or deformation at bushing or ball joint mounts, compromising alignment and suspension integrity.
Symptoms:
Clunking or popping noises when turning, often caused by a deformed knuckle or worn bearing contact points.
Steering feels heavy, loose, or unresponsive, due to misalignment or weakened linkage geometry.
Vehicle pulls to one side, even with the wheel centered, from camber or toe angle distortion.
Uneven tire wear, especially on one edge, from compromised suspension geometry.
Steering wheel vibration, particularly at high speeds, from imbalance or bent knuckle arms.
Brake pulsation or uneven braking, if the knuckle misaligns the caliper or rotor mounting surface.
Visible cracks, rust, or deformation on the knuckle during inspection, especially near ball joint or bushing seats.
Loose suspension components, like ball joints or control arms, due to distorted mounting points.
Persistent alignment issues, where toe or camber settings won’t hold after adjustment.
Grease seepage or oil leaks near the knuckle, often from damaged hub seals or bearing wear.
Parts to Replace
Front Passenger Right 1663301020 The Genuine Mercedes-Benz Steering Knuckle part number 1663301020 / 166 330 10 20 is an essential component that plays a significant role in ensuring the smooth functioning of your Mercedes-Benz.
Front Driver Left 1663300920 The Genuine Mercedes-Benz Steering Knuckle part number 1663300920 / 166 330 09 20 is a top-of-the-line replacement part for your Mercedes-Benz vehicle.
P0299-P2263 indicate turbo under/overboost, timing misalignment, or boost system faults from leaks, actuator, sensor, or turbo issues.
Why it happens:
Turbocharger failure typically occurs due to oil starvation, contamination, excessive heat, foreign object damage, or poor maintenance practices.
Symptoms:
Noticeable loss of power and sluggish acceleration, especially when climbing hills or overtaking.
Excessive exhaust smoke, often blue or gray, caused by oil leaking into the exhaust system.
Whining, siren-like, or rattling noises during boost, indicating worn bearings or damaged turbine blades.
Check engine light illuminates, often accompanied by fault codes like P0299, P0234, or P2263.
Increased oil consumption, due to internal seal failure allowing oil into the intake or exhaust.
Poor fuel economy, as the engine compensates for reduced boost with richer fuel mixtures.
Boost gauge shows low or erratic pressure, if equipped, signaling underperforming or overboosting conditions.
Visible oil leaks around the turbo housing, especially near the compressor or turbine seals.
Unusual vibrations or engine surging, caused by inconsistent boost delivery.
Delayed throttle response, making the vehicle feel unresponsive or laggy under load.
Parts to Replace
Driver Side 2780902300 is an OEM oil feed tube designed to supply pressurized engine oil to the turbocharger, ensuring proper lubrication and cooling of the turbo’s internal components.
Driver Side 2782001000 is an OEM coolant feed line engineered to circulate coolant through the turbocharger, helping regulate turbo temperatures and prevent overheating during high-load operation.
P0171 and P052E indicate lean condition and PCV valve issues from vacuum leaks, low fuel pressure, or crankcase imbalance.
Why it happens:
PCV valve failure typically occurs due to sludge buildup, oil contamination, or spring fatigue, which restricts airflow or causes the valve to stick open or closed.
Symptoms:
Check engine light illuminates, often with codes like P052E, P0171, or P0300 due to air-fuel imbalance or crankcase pressure issues.
Rough idle or engine stalling, especially at low RPMs, from vacuum leaks or incorrect mixture caused by a stuck valve.
Increased oil consumption, as a stuck-open valve can draw oil into the intake and combustion chambers.
Oil leaks or blown gaskets, due to excessive crankcase pressure from a clogged or stuck-closed valve.
Blue or black exhaust smoke, indicating oil being burned or a rich fuel mixture from improper ventilation.
Whistling or hissing noises, caused by vacuum leaks or a partially stuck valve fluttering under load.
Sludge buildup in the engine, from trapped blow-by gases and moisture contaminating the oil.
Poor fuel economy, as the ECU compensates for incorrect air-fuel ratios.
Fouled spark plugs, from oil vapor or rich mixtures affecting combustion.
Strong fuel or oil odor, especially near the engine bay or exhaust, due to vapor misrouting.
Parts to Replace
Mercedes Crankcase Vent Valve 2780100431 The Genuine Mercedes-Benz Engine Crankcase Vent Valve with part number 2780100431 / 278 010 04 31 is a high-quality and reliable replacement part for your Mercedes-Benz vehicle.
Elring Gasket Part # 593910 The Elring Engine Oil Separator Filter Gasket is a high-quality replacement for the original oil separator filter gasket of your Mercedes-Benz.
P0116 and P0118 indicate coolant temperature sensor faults - erratic or high input - causing poor fuel economy, overheating, or drivability issues.
Why it happens:
Engine coolant temperature sensor failure typically occurs due to prolonged heat exposure, corrosion, electrical faults, or contamination from degraded coolant.
Symptoms:
Check engine light turns on, often with codes like P0116 or P0118 due to erratic or high voltage signals.
Poor fuel economy, as the ECU may enrich the mixture unnecessarily if it thinks the engine is cold.
Hard starting or extended cranking, especially in cold weather, from incorrect air-fuel mixture.
Rough idle or engine stalling, caused by unstable fuel delivery based on faulty temperature readings.
Overheating or cooling fan issues, since the ECU may not activate the fan at the right time.
Black smoke from the exhaust, due to an overly rich mixture from false cold engine signals.
Fluctuating or inaccurate temperature gauge, reflecting inconsistent sensor output.
Poor engine performance, including hesitation or surging, from incorrect ignition timing or fuel trim.
Radiator fan running constantly or not at all, depending on how the ECU interprets the sensor signal.
Failed emissions test, as incorrect combustion leads to higher pollutant output.
NTK EF0023 - Engine Coolant Temperature Sensor is a high-quality aftermarket alternative to the OEM Mercedes-Benz sensor, offering reliable performance and compatibility with a wide range of Mercedes models.
P0087, P0088, P2293, and P0191 indicate abnormal fuel pressure from sensor, regulator, pump, or circuit faults affecting performance.
Why it happens:
High-pressure fuel pump failure typically results from fuel contamination, lack of lubrication, excessive heat, mechanical wear, or neglected maintenance.
Symptoms:
Hard starting or extended cranking, especially after the vehicle has been sitting, due to insufficient fuel pressure buildup.
Loss of power under load, such as during acceleration or hill climbs, from inadequate fuel delivery to meet engine demand.
Engine misfires or hesitation, often caused by inconsistent fuel pressure disrupting combustion timing.
Check engine light, frequently accompanied by codes like P0087, P0088, P0191, or P2293.
Poor fuel economy, as the ECU compensates for pressure irregularities by adjusting fuel trims.
Surging or bucking during acceleration, from erratic fuel pressure spikes or drops.
Rough idle or stalling, especially at low RPMs, due to unstable fuel delivery.
Whining or buzzing noises from the fuel tank or engine bay, indicating pump strain or cavitation.
Fuel odor or visible leaks, if the pump or associated lines are compromised.
Increased exhaust emissions, from rich or lean mixtures caused by improper fuel atomization.
Parts to Replace
Right Part # 0261520221 The Bosch Direct Injection High Pressure Fuel is a top-of-the-line fuel pump that is engineered to deliver reliable performance and efficient fuel delivery for your Mercedes-Benz.
P0201-P0208, P0300, P0171, and P0174 indicate injector faults, misfires, and lean conditions from fuel, air, or sensor issues.
Why it happens:
Fuel injector failure typically occurs due to internal clogging from fuel contaminants, electrical faults, heat-induced wear, or seal degradation over time.
Symptoms:
Rough idle or engine stalling, especially at low RPMs, due to inconsistent fuel delivery.
Engine misfires, often caused by clogged or malfunctioning injectors disrupting combustion.
Check engine light illuminates, typically with codes like P0201-P0208 or P0300.
Poor fuel economy, as faulty injectors may over- or under-deliver fuel.
Strong fuel odor, indicating a leaking injector or one stuck open.
Hard starting, particularly when cold, due to incorrect air-fuel mixture.
Loss of power or hesitation during acceleration, from uneven fuel distribution.
Increased exhaust emissions or failed emissions test, caused by rich or lean mixtures.
Fuel leaks around the injector rail, visible as wetness or fuel pooling.
Engine vibration, especially under load, from one or more cylinders not firing properly.
Parts to Replace
Bosch 62437 - Fuel Injector is a high-pressure direct injection unit engineered for precise fuel atomization and optimal combustion in modern Mercedes engines.
Bosch Fuel Injector Kit Part # 5141125-Kit is a premium OEM-grade solution designed for high-performance Mercedes-Benz engines, combining Bosch precision with genuine Mercedes components.
P0562 and P2503 indicate low system voltage, typically caused by a failing alternator, weak battery, corroded terminals, or wiring faults.
Why it happens:
Alternator failure typically occurs due to worn bearings, voltage regulator faults, heat damage, fluid contamination, or excessive electrical load.
Symptoms:
Battery warning light illuminates, often shaped like a battery or labeled “ALT” or “GEN,” signaling charging system issues.
Dim or flickering headlights, especially at idle or under load, due to inconsistent voltage output.
Electrical accessories malfunction, such as slow power windows, erratic dashboard lights, or weak HVAC blower performance.
Dead or repeatedly drained battery, as the alternator fails to recharge it while driving.
Engine stalls or struggles to start, from insufficient voltage to ignition and fuel systems.
Whining or grinding noises, caused by worn bearings or internal alternator wear.
Burning rubber or electrical smell, often from a slipping belt or overheating alternator components.
Dashboard gauges behave erratically, including speedometer, tachometer, or infotainment resets.
Frequent jump-starts needed, even with a new battery, indicating poor charging.
Voltage readings below 13.5V or above 14.5V, when tested with a multimeter while the engine is running.
Parts to Replace
Valeo Mercedes Alternator - 439741 is a premium OEM-grade alternator designed specifically for various Mercedes-Benz models equipped with the M278 4.7L Bi-Turbo V8 engine.
P0751, P2700, and P2711 indicate solenoid or gear engagement faults causing harsh shifts, slipping, delayed response, and drivability issues.
Why it happens:
Transmission valve body solenoid failure typically occurs due to fluid contamination, overheating, electrical faults, worn seals, or internal mechanical wear disrupting hydraulic control.
Symptoms:
Harsh or delayed gear shifts, especially when moving from Park to Drive or Reverse, due to solenoid timing issues.
Unpredictable upshifts or downshifts, where the transmission changes gears erratically or at the wrong time.
Slipping transmission, where engine RPM increases but vehicle speed doesn’t, indicating poor clutch engagement.
Stuck in one gear or limp mode, often second or third, as the ECU limits shifting to protect the transmission.
Delayed engagement when shifting, such as a pause before the car moves after selecting Drive or Reverse.
Jerky or banging shifts, caused by solenoids failing to regulate hydraulic pressure smoothly.
Check engine light or transmission warning, often accompanied by codes like P0751, P2700, or P2711.
Failure to downshift, especially when slowing down or coming to a stop, due to stuck or unresponsive solenoids.
Overheating transmission, from improper fluid flow or pressure regulation.
Fluid contamination, where dirty or burnt transmission fluid affects solenoid operation and valve body function.
Parts to Replace
Mercedes Solenoid Valve 2202771098 The Bosch Automatic Transmission Valve Body Solenoid is a high-quality replacement part that is designed to ensure the smooth operation of your Mercedes-Benz.
Mercedes Solenoid Valve 2202770998 The Bosch Automatic Transmission Valve Body Solenoid is the perfect fit for your Mercedes-Benz vehicle with part number 220 277 09 98.
Transmission mount failure typically occurs due to rubber deterioration from heat, fluid contamination, age, or excessive drivetrain movement stressing the mount structure.
Symptoms:
Excessive vibration, especially during acceleration or idling, due to the mount failing to dampen drivetrain movement.
Clunking or banging noises, often heard when shifting gears or going over bumps, from the transmission shifting excessively.
Harsh or delayed gear shifts, caused by misalignment or unstable transmission positioning.
Visible engine or transmission movement, especially when revving in gear, indicating a loose or broken mount.
Unusual drivetrain misalignment, which may lead to poor handling or uneven tire wear.
Increased engine noise, as vibrations and mechanical sounds are no longer isolated from the cabin.
Jerky acceleration or deceleration, from drivetrain components shifting under load.
Dashboard or interior rattling, particularly at low speeds or when idling in gear.
Transmission fluid leaks, if excessive movement stresses seals or lines.
Check engine or transmission warning light, in severe cases where shifting or alignment is affected.
Parts to Replace
OEM Mercedes Transmission Mount 1662401118 is a genuine or OE-equivalent component designed to isolate drivetrain vibrations and maintain proper transmission alignment.
B24D4 and B24D5 indicate tailgate motor communication or obstruction faults, typically caused by motor failure, wiring issues, or physical blockage preventing smooth tailgate operation.
Why it happens:
Tailgate lift motor failure typically occurs due to electrical faults, worn gears, moisture intrusion, or physical obstructions, which prevent the motor from operating smoothly or receiving proper power.
Symptoms:
The tailgate won’t open or close electronically, even though the button or key fob is pressed.
Intermittent or sluggish operation, where the liftgate starts moving but stalls or reverses unexpectedly.
Unusual noises like grinding, clicking, or buzzing, indicating worn gears or internal motor strain.
Liftgate stops mid-cycle, often due to overheating, obstruction, or failing motor windings.
No response from control switches, despite confirmed power supply and functional fuses.
Manual operation feels heavy or stiff, suggesting the motor isn’t disengaging properly.
Liftgate opens partially then reverses, often caused by sensor miscommunication or motor torque loss.
Burning smell or heat near the motor housing, a sign of electrical overload or internal failure.
Frequent blown fuses or tripped relays, pointing to short circuits or excessive current draw.
Diagnostic codes like B24D4 or B24D5, indicating motor malfunction or obstruction detected by the control module.
B1B48, B1B50, and U0155 indicate parking sensor and instrument cluster faults-causing warning lights, sensor errors, and communication loss.
Why it happens:
Parking aid sensor failure typically occurs due to dirt or moisture intrusion, sensor damage, wiring faults, or control module glitches, all of which disrupt accurate object detection.
Symptoms:
No audible beeps or visual alerts when reversing or approaching obstacles, indicating sensor inactivity.
False alarms or constant beeping, even when no object is nearby, due to sensor misreading or obstruction.
“Park Assist Blocked” or “Parking Aid Malfunction” messages on the dashboard, often triggered by sensor or wiring faults.
Inconsistent detection range, where the system sometimes works and sometimes doesn’t.
Sensors fail to activate in reverse gear, suggesting a control module or gear signal issue.
Visible damage, dirt, or moisture on the sensor face, which can impair ultrasonic signal transmission.
One side of the system not responding, such as only rear or only left sensors failing, pointing to localized faults.
Intermittent operation, where the system works after a restart but fails again shortly after.
Clicking sound missing from sensor when tested by ear, indicating a dead or non-functioning unit.
Diagnostic trouble codes (like B1B48 or B1B50) stored in the control module, confirming sensor or circuit failure.
Parts to Replace
Front Outer 21254201189040 The Genuine Mercedes-Benz Parking Aid Sensor part number 21254201189040 is a high-quality replacement part designed to ensure the proper functioning of your car’s parking aid system.
Front Outer 2125420118649999 is an OEM ultrasonic distance sensor designed to support Parktronic and active parking assist systems across a wide range of Mercedes-Benz models.
Front and Rear 2125420018 The Genuine Mercedes-Benz Parking Aid Sensor is a top-quality product that is designed to enhance your driving experience.
Bosch Mercedes Parktronic Sensor 2125420018 The Bosch Parking Aid Sensor part number 0263009638 is a high-quality replacement part that guarantees reliable performance and accurate readings.
Hella Mercedes-Benz Parking Aid Sensor 358141371 is a high-quality, OE-style ultrasonic sensor designed for Mercedes-Benz Parktronic systems, offering reliable object detection and seamless integration.
eEuroparts offers a wide selection of OEM and well-reviewed aftermarket parts chosen for compatibility with Mercedes-Benz vehicles. Parts are listed with fitment details and trusted brand options to help you find components that are appropriate for routine maintenance and common repairs.
Exceptional Delivery, Unmatched Logistics
We know that every moment counts when your car is out of commission. That’s why we focus on getting your parts to you as quickly as possible. Our efficient logistics network and fast shipping mean minimal downtime for your vehicle.
Competitive Prices, Superior Value
Our catalog includes everything from timing chains, camshaft adjusters, and PCV valves to wheel bearings, control arms, and fuel pumps, sourced to meet or exceed OE standards. Whether you prefer genuine Mercedes-Benz parts or trusted aftermarket brands, we offer top-tier quality at better-than-dealer pricing.
Trusted Excellence
Our catalog includes parts from top-tier brands like Bosch, INA, ZF, Pierburg, Elring, Lemforder, and Rein. Whether you're resolving transmission issues, electrical faults, or suspension wear, our parts meet or exceed OEM standards for fit, durability, and performance.
Conclusion
Whether you’re replacing worn items or addressing a specific fault, use these listings to identify likely parts and plan repairs. For vehicle-specific advice, consult a trusted technician to confirm fitment and service steps before installation.
Frequently Asked Questions
What common issues do GL550 and GLS550 owners experience?⌄
Most owners report air suspension sagging, oil leaks from valve covers or turbo lines, and premature wear in control arms. These issues become more noticeable as mileage increases.
Why does my GL550 or GLS550 sit low or lean on one side?⌄
This is usually caused by failing air suspension components like air struts, air springs, or the compressor. The SUV may drop overnight or show a suspension warning.
Is maintenance on the GL550/GLS550 expensive? ⌄
Maintenance costs can be higher due to the V8 twin-turbo engine and advanced suspension system. Regular service and using reliable OEM or premium aftermarket parts help keep costs manageable.
Why does my GL550/GLS550 show a loss of power during acceleration?⌄
Loss of power often points to worn spark plugs, boost leaks, dirty sensors, or early turbo wear. A simple inspection of coils, hoses, and sensors usually identifies the cause.
What causes a burning oil smell in the GL550 or GLS550? ⌄
These models commonly develop valve cover gasket leaks or oil leaks around turbo oil lines. Heat from the engine makes the smell stronger, especially after longer drives.
What Customers Say on Trustpilot
★★★★★
I have experience with eEuroparts… "I have experience with eEuroparts longtime and they good parts of Mercedes and all fits my car. They have excellent quality parts.” - Mohamed Abbas
★★★★★
eEuroparts My No 1 go to. "eEuroparts has good prices and hassle free service. They have lots of parts for my North American MB Sprinter but you have to know what you need as they often default to the European Sprinter models and not all the parts are the same. Having said that. I got high quality parts at a great price and they fit perfectly. Lots of quality brand names to choose from and good selection. This is now the first place I look for parts." -Daniel R
Shop now at eEuroparts.com - your trusted partner for quality automotive parts at unbeatable prices!
Apr 13, 2025Celebrating 25 Years of Excellence at eEuropartsSince its inception in 2000, eEuroparts has been dedicated to providing European car owners and enthusiasts throughout the United States with top-quality Genuine, OEM, and premium aftermarket parts. What started as a small passion project has evolved into a prominent player in the auto parts sector, renowned for its dependability, swift shipping, and unparalleled customer service. Over the years, we've successfully processed more than 20 million orders, ensuring that premium European parts are accessible no matter your location.
Aug 18, 2024Saab 9-3 Lower Control Arm Symptoms and ReplacementThe Saab 9-3 is cherished by automotive enthusiasts for its unique design and turbocharged performance, representing a high point in Swedish automotive engineering. This model has fostered a dedicated following, even after Saab's exit from the automotive market. However, like many vehicles that age, the Saab 9-3 presents maintenance challenges, particularly regarding its lower control arm—a key element of the suspension system.
Aug 12, 20242018 Mercedes-Benz Sprinter 2500 Oil Cooler Leaks ExplainedIf you're the proud owner of a 2018 Mercedes-Benz Sprinter 2500, you value its reliability for a variety of uses, from deliveries to road trips. However, like all vehicles, it's not without its issues, with oil cooler leaks being a common concern among owners. While the term oil cooler may sound technical, this guide will simplify the topic and provide you with essential insights.
Aug 6, 20242013 Mercedes-Benz G550 Secondary Air Pump IssuesThe 2013 Mercedes-Benz G550 is a luxurious SUV recognized for its impressive performance and off-road capabilities. A crucial component that ensures its smooth operation and compliance with strict emissions standards is the secondary air pump. This essential part of the emissions system reduces harmful exhaust emissions during the initial startup phase, particularly when the engine is cold.
