2017 Mercedes-Benz GLA Problems: 15 Known Issues

On the 2015-2019 Mercedes-Benz GLA M133, the M133 turbo's wastegate is actuated by a mechanical rod and flapper valve that runs at very high exhaust gas temperatures. On GLA45 (and its CLA45/A45 siblings) the flapper bushing and actuator rod wear until there is visible free play, so the wastegate no longer seals the bypass ports. Boost bleeds past, the ECU sees target boost it cannot reach, and it stores P0299 (turbocharger 'A' underboost) and cuts the car to limp/reduced-power mode - often intermittently, restoring full power after a restart until it happens again. Owners describe rattling from the turbo at part throttle and a sudden dead-pedal on a pull. Dealers routinely quote a complete turbo assembly ($5,500-6,000), but the failure is usually confined to the wastegate hardware.

On the 2015-2020 Mercedes-Benz GLA M270, the M270 uses a two-stage variable-displacement oil pump whose output is switched by a PWM solenoid (Y130) mounted inside the oil pan, with its wiring harness routed through the pan and out an oil-tight connector. The solenoid winding fails open, or the in-pan harness insulation chafes, and the ME control unit sets P06DA00 - 'electrical fault / open circuit in the valve actuation of the engine oil pump.' The engine defaults to one pressure stage, so it usually still drives, but owners report an oil pressure or engine warning, a check engine light that returns immediately after clearing, and in some cases a low-oil-pressure red warning at hot idle. Because the valve lives inside the sump, the repair is far more invasive than the part cost suggests - on 4MATIC cars the front subframe and driveshaft have to come down to drop the pan.

On the 2015-2020 Mercedes-Benz GLA, the GLA's M270 turbo four-cylinder petrol engines are widely documented to suffer timing chain elongation and tensioner/guide wear, usually presenting between roughly 40,000-80,000 mi. A loose chain produces a distinctive rattle for the first few seconds after a cold start until oil pressure loads the tensioner. A related defect is the camshaft tone/reluctor ring slipping, throwing timing-correlation faults. Left unaddressed, a stretched chain can jump time and cause valve-to-piston contact and major engine damage.

On the 2015-2023 Mercedes-Benz GLA, on the M270 2.0T engine the partial-load crankcase ventilation valve (Y58/2) is an electrically actuated valve in the crankcase ventilation system (and carries over in modified form on the M260). The valve itself or its wiring and connections can fail, and on early cars its connector could be fitted reversed with the neighbouring thermostat heating element (R48) connector. Owners get a check engine light and a stored P052E (often shown as P052E71 - 'Positive Crankcase Ventilation Regulator Valve Performance actuator stuck'). On the related M274, Mercedes' bulletin describes the valve as part of the intake line assembly, which is why dealer quotes can be high relative to the failed part.

On the 2015-2020 Mercedes-Benz GLA M270, the water pump on the M270 engine fails, causing loss of coolant circulation and rapid overheating. The pump fails internally or leaks, and failure is often sudden with no warning. Common between 50,000-90,000 miles.

On the 2015-2023 Mercedes-Benz GLA, gLA diesels (GLA 200d/220d), popular in Germany and the EU, develop clogged EGR valves and diesel particulate filters from soot buildup, plus AdBlue/SCR (NOx reduction) faults. EGR carbon fouling causes rough idle, reduced power and emissions faults; DPF blockage triggers limp mode if regeneration can't complete (common with short urban trips). AdBlue/SCR issues include crystallization from irregular use, sensor/NOx-sensor faults, level/quality warnings and countdown-to-no-start messages. The OM651 also shares timing-chain-stretch tendencies.

On the 2015-2020 Mercedes-Benz GLA, the X156 GLA's 7G-DCT 7-speed wet dual-clutch transmission (type 724.0) is prone to low-speed shudder/judder, jerky or delayed engagement, and clutch slip, typically emerging from ~40,000-75,000 mi (60,000-120,000 km). Root causes are wet multi-plate clutch wear, degraded/contaminated DCT fluid, and failure of the mechatronics control unit that manages clutch pressures. Stop-go urban driving and skipped fluid services accelerate it. Once shuddering begins, worn clutch packs can progress to a no-drive condition within a few thousand km.

On the 2015-2020 Mercedes-Benz GLA, two distinct steering faults recur on the X156. First, a safety recall covers 2017-2018 GLA250 and AMG GLA45 (with 2017 CLA250/B250e and 2017-2018 AMG CLA45): the bore hole in the steering shaft for the universal joint bearing allows excessive movement, and over time the bearing and U-joint can separate, causing a total loss of steering control. Second, separate from the recall, owners report an intermittent red 'Power Steering Malfunction - See Operator's Manual' message with heavy, unassisted steering effort, traced on these cars to the electric power steering rack's integrated motor/control unit or to a corroded or poorly seated connector at the rack - MBUSA's service action for related cars was to replace the connector and inspect the EPS rack, replacing it as needed.

On the 2015-2023 Mercedes-Benz GLA, mercedes communications directly support discharged 12V starter batteries and no-start conditions on both GLA generations. Communications 10157073, 10157076, 10158199 and 10158370 cover discharged batteries, no-start complaints and excessive quiescent current on earlier GLA vehicles. Communication 10217159 identifies a later bus-keepawake path in the headlamp, ALC, instrument cluster, SAM, PTCU or ESP control units, with U116000 and a software-first remedy. Communication 11018206 warns that a discharged battery does not automatically require replacement and requires onboard-data analysis to identify the cause. These records do not establish one universal relay, charging-strategy or 48V-battery cause for every 2015-2023 GLA.

On the 2015-2023 Mercedes-Benz GLA, gLA infotainment units suffer black/frozen screens and spontaneous reboots. On H247 cars this is the NVIDIA-Tegra-based MBUX head unit, whose software can fail to boot or reboot ~50 seconds after startup, disabling the rearview camera image (the basis of NHTSA recall 21V354, which covers 2021 GLA250, AMG GLA35 and AMG GLA45 among 2019-2021 MB models). On X156 cars the COMAND/Audio 20 system has analogous software bugs. Weak 12V battery voltage dips and heat aggravate it.

On the 2015-2024 Mercedes-Benz GLA, the GLA hides its reversing camera behind a motorized flap in the tailgate handle trim, which is supposed to swing open when reverse is selected and close again to keep the lens clean. The small flap motor, its position sensor, and especially the flex wiring running into the moving assembly fail: the flap stalls shut, opens then immediately snaps closed, cycles noisily while in reverse, or the display shows a black screen or a 'camera unavailable' message. Owners have traced individual cases to a broken conductor in the flap harness (a snapped red wire soldered back together restored function), to a seized/dirty flap mechanism, and to corroded connectors at the tailgate pass-through. It recurs across the X156 years and continues to be reported on later cars.

On the 2015-2023 Mercedes-Benz GLA, the 4MATIC transfer case on the GLA develops a whining or humming noise at highway speeds. The noise is caused by gear wear inside the power take-off unit that distributes torque to the rear axle. More common on vehicles that have seen off-road use or aggressive driving.

On the 2015-2023 Mercedes-Benz GLA, on 4MATIC GLA250/GLA220d cars the rear differential carrier assembly is a documented weak point, producing whine, growl, or clunk from the rear (especially on/off throttle and cornering), often at surprisingly low mileage (~50,000-70,000 mi). The differential uses a very small fluid volume (under ~1 liter) that breaks down and contaminates; some units also had marginal bearings. This is distinct from the transfer-case/PTU noise and originates in the rear axle carrier itself. A neglected unit can develop heavy bearing/gear wear.

On the 2015-2023 Mercedes-Benz GLA, the GLA's panoramic roof drains water through four small tubes that run down the A- and C-pillars. Pollen, grit and - in documented GLA cases - a broken plastic bracket from the sunroof track itself block the tube or the drain channel, so water backs up over the channel lip and runs down inside the pillars. Owners find soaked front or rear footwell carpet, a persistent damp/musty smell, and fogging windows. Because control modules and connectors sit low in the footwell and under the seats on these cars, sustained water ingress is what kills them: water damage from clogged roof drains is the single most common cause of Mercedes SAM/body-control module failure, which then presents as random electrical faults and parasitic drain. Not related to the separate roof-panel bonding recall.

On the 2015-2020 Mercedes-Benz GLA, gLA owners report the panoramic glass roof spontaneously cracking or shattering, the subject of class-action litigation against Mercedes over allegedly weak/stress-prone panoramic glass. Separately, Mercedes recalled certain 2015-2020 GLA250 and 2015-2016 AMG GLA45 vehicles (with other 2014-2020 models, NHTSA 21V-197 and its expansion 23V-854) because the fixed front roof panel between the windshield and the panoramic sunroof may have been improperly bonded during a prior repair and could detach in motion — a road-debris/crash hazard. A further recall (NHTSA 18V-912) covers 2018-2019 GLA250 vehicles whose panorama sunroof glass bonding may develop minor leaks near the window airbag, which could impair its electrical contacts.