VOLVO
ECM-6890 - Bypass valve, charge air cooler (CAC) (SAE J1930). Signal too high
System
Engine Control Module (ECM)
Volvo models this fault code applies to
Applies to the following models:
3 modelsC30 (2007–2013), S40 (2004–2013), V50 (2004–2013)
What does this fault code mean?
The ECM watches the charge air cooler bypass valve through the feedback from the position sensor on it. If the signal is too high or too low with the ignition on, the code is set. The cause may be poor contact, a signal wire shorted to voltage or ground, or a damaged bypass valve.
Possible causes
- Loose connection, contact resistance or oxidation in the terminals
- Position sensor signal line shorted to voltage
- Open circuit in the signal ground lead to the position sensor
- Damaged bypass valve
- Open circuit or short to ground in the power supply to the position sensor
- Open circuit or short to ground in the signal line to the position sensor
What you can do
- 1Check the plug at the ECM and at the bypass valve for loose contact, contact resistance and oxidation
- 2With the ignition off and the connector disconnected, use a multimeter to check that the leads to the position sensor are intact and have no contact with voltage or ground
- 3Read the code, clear it and road test the car to see whether it returns
- 4If the fault returns, have a workshop check the position sensor and replace the bypass valve if needed
Symptoms you may notice1
- Check engine lamp lit or behaving abnormally
General guidance for car owners. Diagnosis on the car can point to a different cause.