KNOWN FAULTS · Mercedes-Benz

Mercedes-Benz Clase C (W205) C 63 / C 63 S AMG (M177, 4.0 V8) common problems.

2014–2021 · Petrol

Sources are not verified in real time and no entry confirms that your car is affected.

3 known faults with sources

Applies if: Only if fitted with 7G-Tronic. Confirm the gearbox type.

7G-Tronic conductor plateGearbox

Engine / equipment: 7G-Tronic automatic gearbox (722.9) in the C, E, S-Class, ML, GL, SLK, Sprinter…
Period mentioned: 2004 onwards (more failures in 2004–2008)
Symptoms: Gearbox stuck in 2nd or 3rd (limp mode), harsh shifts, delay engaging D or R, gearbox warning often without an engine light; turning off and restarting clears it for a while.
Possible cause described: The conductor plate (the control unit with built-in speed sensors) fails from heat and vibration. Oil leaks through the 13-pin connector are also common.
Check for the garage: Diagnose with Xentry/STAR to see the sub-codes (a basic reader only shows P0700). Check for oil in the gearbox connector.
Cost cited in the source: Approx. €1,400–2,800 (estimate)A rough figure from the original database, not an up-to-date quote.

Applies if: Only if fitted with the automatic gearbox described in the record.

9G-Tronic harsh shiftingAutomatic gearbox

Engine / equipment: 9G-Tronic automatic gearbox (725.0 and 725.1): C-Class W205 and W206, E W212 and W213, CLS, S W222 and W223, GLC, GLE, GLS, SL and SLC
Period mentioned: 2013–2026
Symptoms: Harsh or jerky shifts (especially 1st to 2nd and when cold), vibration, delayed shifts or limp mode; sometimes the gear will not engage from N to D. Codes P073E00 and P07B700.
Possible cause described: Mercedes acknowledges in a technical bulletin complaints of harsh shifts, shudder and limp mode with various causes. In the early years (2014–2016) it is usually software or adaptation rather than mechanical damage; in other cases the pressure sensor built into the gearbox control unit fails.
Check for the garage: Follow the Mercedes bulletin: reproduce the complaint, save the EEPROM, check the oil level, run the Xentry valve flush, update engine, gearbox and shift unit software and perform the standstill adaptation. If it persists, check the control unit.
Cost cited in the source: Software update and adaptation: the most common and cheapest fix; repairing or replacing the control unit costs considerably more (the sources give no comparable figures)A rough figure from the original database, not an up-to-date quote.

Applies if: US bulletin (XENTRY LI07.10-P-080384) for Mercedes-AMG models with the M177 engine; in Europe, ask the dealer.

Engine warning light and loss of power from the throttle body pins (Mercedes-AMG with the M177 V8)Powertrain and engine management

Engine / equipment: Mercedes-AMG with the 4.0 twin-turbo V8 M177 (C 63, E 63, GLC 63, GLE 63, GLS 63 and G 63)
Period mentioned: 2015–2025 (US model years)
Symptoms: The engine warning light comes on and the car may lose power, with throttle codes such as P210185, P213500 or P213600.
Possible cause described: Electrical resistance increases in the pins of the left and right throttle actuator connectors. Mercedes-Benz describes it in its technical note LI07.10-P-080384: the connector pins are replaced with updated ones.
Check for the garage: Ask the workshop to check the connectors of both throttle bodies and apply note LI07.10-P-080384 before replacing the throttle bodies.
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.