VOLVO
ECM-0034 - Bypass valve, charge air cooler (CAC). Signal too low
System
Engine Control Module (ECM)
Volvo models this fault code applies to
This fault code has different meanings depending on model, model year or engine. Select the meaning that applies to your car.
Applies to the following models:
4 modelsC30 (2007–2013), C70 (2006–2013), S40 (2004–2013), V50 (2004–2013)
Show models by year and engine (10)
- Volvo C30 (2007–2013)2007Engine D4204T only
- Volvo C30 (2007–2013)2008–2010Engine D4204T only · Transmission MMT6 only
- Volvo C70 (2006–2013)2008Engine D4204T only
- Volvo C70 (2006–2013)2009–2010Engine D4204T only · Transmission MMT6 only
- Volvo S40 (2004–2013)2005–2006Engine D4204T, D4204T2 only
- Volvo S40 (2004–2013)2007Engine D4204T only
- Volvo S40 (2004–2013)2008–2010Engine D4204T only · Transmission MMT6 only
- Volvo V50 (2004–2013)2005–2006Engine D4204T, D4204T2 only
- Volvo V50 (2004–2013)2007Engine D4204T only
- Volvo V50 (2004–2013)2008–2010Engine D4204T only · Transmission MMT6 only
What does this fault code mean?
The engine control module (ECM) keeps watch on the charge air cooler bypass valve and has registered a signal to the valve that is too low. The cause is most often a short to ground in the signal wire, but a break in the power supply or a faulty valve can also cause the fault.
Possible causes
- Short circuit to ground in the signal wire
- Open circuit in the power supply to the valve
- Faulty bypass valve on the charge air cooler (CAC)
What you can do
- 1With the ignition off, check the connector to the bypass valve for looseness, contact resistance and oxidation
- 2Unplug the connector and use a multimeter to check that the signal wire to the valve has no contact with ground (the body)
- 3Erase the fault codes, take the car for a test drive and see whether the fault returns
- 4If the fault returns and the wiring is sound, have a workshop replace the bypass valve
Symptoms you may notice2
- Car feels weak, lacks power or performs poorly
- Warning symbol and text message in the display
What the fault can affect1
- Engine speed (RPM) may be limited
General guidance for car owners. Diagnosis on the car can point to a different cause.