KNOWN FAULTS · Mercedes-Benz

Known faults for the Mercedes-Benz SLK (R171).

2004–2011 · Petrol

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

4 known faults with sources

Engines: SLK 200 Kompressor (M271) (Petrol) · SLK 280 / 350 (M272) (Petrol) · SLK 55 AMG (5.4 V8) (Petrol)

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.

Engines: SLK 200 Kompressor (M271) (Petrol)

M271 chain and camshaft adjustersTiming system

Engine / equipment: M271 1.8 Kompressor / CGI (C 180/200 W203 and W204, E 200 W211/W212, CLK 200, SLK 200)
Period mentioned: 2002–2015
Symptoms: Rattle for 2–3 seconds or more on a cold start; engine light for camshaft timing deviation.
Possible cause described: A single-row chain that stretches and cast-iron camshaft adjusters whose teeth wear. On later versions the hydraulic tensioner fails more often.
Check for the garage: Listen to a cold start, read timing fault codes and check the chain replacement history.
Cost cited in the source: €1,500–3,000A rough figure from the original database, not an up-to-date quote.

Engines: SLK 200 Kompressor (M271) (Petrol) · SLK 280 / 350 (M272) (Petrol) · SLK 55 AMG (5.4 V8) (Petrol)

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

13-pin connector leak on the 722.6 gearboxAutomatic gearbox

Engine / equipment: 722.6 five-speed automatic (5G-Tronic), not the 7G-Tronic: C-Class W203, E-Class W210 and W211, CLK, S-Class W220, ML W163, SLK, SL R230, Vito and Sprinter with this gearbox
Period mentioned: 1996–2013
Symptoms: Oil around the electrical connector on the side of the gearbox, harsh shifts or slipping, delayed engagement and limp mode: the car stays in one gear (usually 2nd and reverse after a restart) and the engine light comes on.
Possible cause described: The plastic adapter of the 13-pin connector has O-rings that harden and let oil out. Oil can wick up inside the wiring to the gearbox control unit and damage it. If the problem persists after replacing the connector, there may be oil in the harness, a damaged wire or a conductor plate fault.
Check for the garage: Read the gearbox control unit codes before switching off if possible (a restart can clear them). Look for oil at the connector and, with it unplugged, on its pins and at the control unit plug. According to the service bulletin, the connector should only be removed with gearbox oil below 50 °C to avoid damaging the conductor plate, and the harness must be routed without tension.
Cost cited in the source: Connector adapter: about $15–20 in parts (US prices quoted in the sources), plus the lost fluid; labour extra. If oil has reached the control unit, the repair is bigger.A rough figure from the original database, not an up-to-date quote.

Engines: SLK 280 / 350 (M272) (Petrol)

M272 / M273 balance shaft sprocketTiming system

Engine / equipment: M272 V6 (280, 300, 350) and M273 V8 (450, 500, 550) in the C, E, CLK, CLS, SLK, ML, GL, R, S and CL
Period mentioned: 2004–2008 (engines below serial number 2729..30 468993)
Symptoms: Engine light with P0016 and P0017 (1200 and 1208 on Mercedes diagnostics), rattle on start-up, hesitation, misfires and, in severe cases, stalling.
Possible cause described: Balance shaft sprocket (M272) or timing idler gear (M273) made from metal that is too soft: the teeth wear, the chain goes slack and the timing slips. Mercedes changed the material in mid-2008.
Check for the garage: Compare the engine serial number with the 2729..30 468993 cut-off, read cam correlation codes and, if in doubt, inspect the sprocket with a borescope. First rule out the cam adjuster magnet (a cheap fault).
Cost cited in the source: Engine-out repair: over €3,700 (converted from dollars)A rough figure from the original database, not an up-to-date quote.