Mercedes-Benz W164 EGR valve faults and fault codes
My W164 EGR valve sticks and the car is sluggish, what causes it?
A common cause is carbon deposit that jams the valve stem. The car then runs poorly and the engine warning light comes on. The valve should be cleaned or, if necessary, replaced. The fault can also look like an EGR fault even though the cause is elsewhere.
What do W164 EGR fault codes 2511-1, 2355-2 and 2616-2 mean?
2511-1 is a signal fault in the EGR valve position control. 2355-2 means the air mass is too high. 2616-2 indicates a control error of the exhaust pressure sensor, where the pressure is too low. Codes 2069-8 and 2070-8 relate to monitoring of the exhaust gas temperature sensor when cold.
What should I check as the cause of W164 EGR codes before replacing the valve?
Check the joints of the intake pipes leading from the turbo for leaks and clean the mass air flow sensors. A new intake pipe alone does not necessarily clear the code. Sticking turbo vanes can also cause the same symptoms, so the condition of the turbo should be checked.