Diagnostic Trouble Code (DTC) Information ECM-641A

Condition

Fig 1: Identifying Camshaft Reset Valve (Continuous Variable Valve Timing (CVVT))

Courtesy of VOLVO CARS OF NORTH AMERICA.

The engine control module (ECM) checks the actual and desired value of the reset valve for the exhaust camshaft (Variable valve timing (VVT)). If these do not correspond the control module interprets it as a fault and diagnostic trouble code (DTC) ECM-640A is stored.

Cleaning (controls alternately between maximum and minimum current to shake off dirt) is carried out before the code is stored. This occurs either when the ignition is switched off or when the fuel shut-off system cuts in.

Diagnostic trouble code (DTC) ECM-641A can be diagnosed when the engine is running.

Substitute Value

Shutting off the variable camshaft.

Possible Source

Faulty signal

The timing belt has jumped off the cogs
Low oil pressure or poor oil grade
Defective exhaust camshaft (Variable valve timing (VVT)) reset valve.

Fault symptom[s]

Uneven idle
The engine misfires.