Diagnostic Trouble Code (DTC) Information ECM-6404

Condition

Fig 1: Identifying Variable Valve Timing (VVT) Unit

Courtesy of VOLVO CARS CORPORATION

The engine control module (ECM) checks that the actual camshaft angle position (actual value for the camshaft shift angle) corresponds to the requested angle position (target value for the camshaft shift angle). The diagnostic trouble code (DTC) is stored if the value for the actual camshaft angle position is higher (signal too high) or lower (signal too low) than the control module target value for the camshaft angle position.

The fault code is diagnosed with the engine running and catalytic converter heating in progress (engine temperature between -10 and 80 °C).

Substitute Value

None.

Possible Source

Signal too high

Short-circuit to supply voltage in the signal cable.
Poor engine oil quality
VVT-unit tightened with too high torque against camshaft.
Damaged camshaft reset valve
Mechanical fault in the continuous variable valve timing (CVVT) unit.

Signal too low

Not detectable.

Fault symptom[s]

Uneven idle
Increased emissions
The engine cuts out when driving.