Diagnostic trouble code (DTC) information ECM-671C

Condition 

Fig 1: Identifying Camshaft Control (CVVT)

Courtesy of VOLVO CARS OF NORTH AMERICA.

The engine control module (ECM) checks the angle of the camshaft (its position in relation to the crankshaft).

If the exhaust camshaft's angle position deviates and is too high during adaption (camshaft is ahead of crankshaft), the Engine control module (ECM) will interpret this as a failure and store a diagnostic trouble code.

The diagnostic trouble code (DTC) can be diagnosed when the engine is hot and the camshaft is in position 0.

Substitute Value 

• The Engine control module (ECM) switches off camshaft control.

Possible Source 

• Poor engine oil quality
• Incorrectly adjusted camshafts
• The timing gear belt has jumped off the cogs
• Damaged camshaft reset valve
• Mechanical fault in the variable valve timing (VVT) unit.

Fault symptom[s] 

• Malfunction indicator lamp (MIL) lit.