Diagnostic trouble code (DTC) information

Condition 

Fig 1: Identifying Camshaft Position Control

Courtesy of VOLVO CARS OF NORTH AMERICA.

When camshaft control is active, the control module checks the position of the camshaft in relation to the position of the crankshaft.

Diagnostic trouble code (DTC) ECM-640A (camshaft intake) or ECM-641A (camshaft exhaust) is stored if the position of the camshaft deviates from the requested position in relation to the crankshaft over a certain amount of time.

Substitute Value 

None.

Possible Source 

Faulty control: 

• Low oil pressure
• Poor oil quality
• Defective reset valve
• Mechanical fault in the variable valve timing (VVT) unit.

Fault symptom[s] 

• Malfunction indicator lamp (MIL) lit.