KNOWN FAULTS · Mercedes-Benz
Mercedes-Benz CLA (C118) / GLA (H247) / GLB 45 S AMG (M139, 2.0) common problems.
2019–2026 · Petrol
Sources are not verified in real time and no entry confirms that your car is affected.
4 known faults with sources
Applies if: The guide covers the CLA C118; the GLA H247 and GLB use the same 7G-DCT gearbox and base.
7G-DCT gearbox and campaigns on the CLA, GLA and GLB (from 2019)Gearbox
- Engine / equipment
- Mercedes CLA C118, GLA H247 and GLB (petrol, diesel, plug-in hybrid and AMG)
- Period mentioned
- 2019 onwards
- Symptoms
- Noises from the 7G-DCT (whine, hum, clunks) and jerks when shifting or pulling away; a clutch that wears faster with short trips or towing.
- Possible cause described
- The guide recommends a software update for jerky shifts. Recalls: an airbag cover that could come loose in a crash and A/C pipe connections on some cars.
- Check for the garage
- Ask for the gearbox software update; check the campaigns by VIN.
- Cost cited in the source
- No verified estimate; ask the garage for a quote.A rough figure from the original database, not an up-to-date quote.
Sources from the original database
View full entryApplies if: US bulletin (XENTRY LI27.19-P-080869) for the CLA (118), GLA and GLB (247) from model year 2024 with the 8G-DCT dual-clutch gearbox; in Europe, ask the dealer.
Intermittent no start, with the engine light and several warnings, caused by the 8G-DCT wake-up line (CLA, GLA and GLB)Electrical and electronic systems
- Engine / equipment
- Mercedes-Benz CLA (118), GLA and GLB (247) with the 8G-DCT dual-clutch gearbox
- Period mentioned
- Model years 2024 onwards (US)
- Symptoms
- Now and then the car will not start, with the engine warning light on and several warning messages on the cluster.
- Possible cause described
- The dual-clutch gearbox control unit stores code P24F100 (wake-up line short to positive); the likely cause is signal timing between the ignition control unit (EZS) and the gearbox control unit. Mercedes-Benz fixes it with new SCN coding of the EZS control unit (note LI27.19-P-080869).
- Check for the garage
- Ask the garage to read the gearbox fault memory and, if P24F100 appears, to apply note LI27.19-P-080869 (SCN coding of the EZS) before replacing the gearbox control unit or the battery.
- Cost cited in the source
- No verified estimate; ask the garage for a quote.A rough figure from the original database, not an up-to-date quote.
Sources from the original database
View full entryApplies if: US bulletin (XENTRY LI46.10-P-078012) for Mercedes-Benz cars with a capacitive steering wheel (code 266) built from 2020; in Europe, ask the dealer.
Assist systems not available messages caused by a steering wheel hands-on detection fault (Mercedes-Benz from 2020)Driver assistance
- Engine / equipment
- Mercedes-Benz with a capacitive steering wheel (code 266)
- Period mentioned
- Built from 2020
- Symptoms
- Messages on the cluster: "Active Emergency Stop Assist not available", "Active Lane Keeping Assist not available" or "Active steering assist not available".
- Possible cause described
- The steering wheel hands-on detection fails: the detection mat, its control unit, the contacts or the wiring. Mercedes-Benz releases new software and SCN coding for the HOSWD control unit (note LI46.10-P-078012).
- Check for the garage
- Ask the garage to apply note LI46.10-P-078012: do not replace the HOSWD control unit, update its software and check the steering wheel contacts, wires and ground connections.
- Cost cited in the source
- No verified estimate; ask the garage for a quote.A rough figure from the original database, not an up-to-date quote.
Sources from the original database
View full entryApplies if: US bulletin (XENTRY LI27.19-P-080823) for model years 2021 to 2023 with the 8G-DCT transmission (724.1); in Europe, ask the dealer.
Transmission fault message and shift to neutral from a false overvoltage (8G-DCT of the A-Class, CLA, GLA and GLB 2021–2023)Automatic gearbox
- Engine / equipment
- Mercedes-Benz A-Class (W177), CLA (118), GLA (247) and GLB (247) with the 8G-DCT dual-clutch transmission (724.1)
- Period mentioned
- 2021–2023 (US model years)
- Symptoms
- Transmission fault message, engine warning light on and the gearbox shifts into neutral (N); the fault disappears after switching off and restarting.
- Possible cause described
- The transmission computer alone detects an overvoltage (over 16 V) and stores code P056300, although no other control unit sees it. Mercedes-Benz fixes it with a transmission software update (technical note LI27.19-P-080823).
- Check for the garage
- Ask the workshop to check whether code P056300 was stored with a voltage of 15.75 to 16.5 V and update the transmission software according to note LI27.19-P-080823.
- Cost cited in the source
- No verified estimate; ask the garage for a quote.A rough figure from the original database, not an up-to-date quote.