P0090 Mercedes A 170 is defined as Knock Sensor Circuit Range Performance (Bank 1 or Single Sensor). This refers to camshaft timing, which in this case is over-retarded. Other serious codes may cause this code to pop up, and they may come with dangerous drivability issues that may expose you to safety risks and cause damage to the engine in the long run.
SymptomsSymptoms of a P0090 Mercedes A 170 diagnostic trouble code may include:
Possible Causes :
You might continue by connecting the scanner to the vehicle diagnostic connector and retrieving all stored codes and freeze frame data. With the valve disconnected, the red voltmeter lead should be attached to the IMRC valve power wire and the black voltmeter lead connected to ground. If the engine displays a miss and there wasn't a code, determine which cylinder is misfiring. If the exhaust manifold is visible, spay or pour a small amount of water on each cylinder exhaust port. Water will evaporate immediately on good cylinders and slowly on the missing cylinder. If this can't be accomplished pull the plugs and check the condition.
Diagnostic trouble code P0090 Mercedes A 170 is not difficult to diagnose and repair. Thus, it always pays to have a qualified technician to look after your vehicle should this error code arise.
Diagnosing this code requires the engine to be in good running shape, without unmetered air entering the engine. If other codes that relates to misfiring condition, lean running or air entering the engine is present, then you must first fix those error codes before P0090 Mercedes A 170.
Fortunately, P0090 Mercedes A 170 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.