Diagnostic trouble code (DTC) information
WARNING: This page is about a different car, the 2004 Volvo S40, 2003 Volvo S40, 2002 Volvo S40, 2001 Volvo S40, and 2000 Volvo S40. However, it is still accessible from the selected car via links, so may be relevant.
Condition
Diagnostic trouble code (DTC) ECM-78 is stored if there is no signal from the engine speed (RPM) sensor to the control module (signal missing) or if the control module detects an abnormal signal (faulty signal).
Substitute Value
- No camshaft diagnostics
- No camshaft control
- Ignition retardation
- No boost pressure diagnostics
- No heated oxygen sensor (HO2S) diagnostics.
Possible Source
Signal missing:
- Open-circuit in the signal cable
- Short-circuit to ground in the signal cable
- Short-circuit to supply voltage in the signal cable
- Faulty engine speed (RPM) sensor.
Faulty signal:
- Loose connections
- Damaged flywheel
- Faulty engine speed (RPM) sensor.
Fault symptom[s]
- The engine misfires
- Malfunction indicator lamp (MIL) lit.