VOLVO
ECM-042C - Rear temperature sensor, catalytic converter. Signal too low
System
Engine Control Module (ECM)
Volvo models this fault code applies to
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, MPS6 only
- Volvo C70 (2006–2013)2008Engine D4204T only
- Volvo C70 (2006–2013)2009–2010Engine D4204T only · Transmission MMT6, MPS6 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, MPS6 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, MPS6 only
What does this fault code mean?
The control module continuously compares the signal from the rear temperature sensor in the catalytic converter with a calculated value, and sets the fault if the signal is too low. The check is made when the ignition is switched on. The causes are contact resistance or oxidation in the connections, open or short circuits in the wiring, or a damaged sensor.
Possible causes
- Contact resistance or oxidation at the sensor connector
- Open or short circuit in the wiring to the sensor
- Damaged temperature sensor
What you can do
- 1Read out the fault code, erase it and check whether it returns at the next ignition on
- 2Switch off the ignition and check the connector to the rear sensor for contact resistance and oxidation
- 3Use a multimeter to check that the signal wire from the sensor has no open circuit and is not shorted to ground or voltage
- 4Look for chafing on the wiring to the rear sensor, especially where it runs close to the exhaust pipe
- 5If the fault remains, have a workshop with diagnostic equipment check the rear temperature sensor
Symptoms you may notice1
- The check engine lamp lights or behaves abnormally
General guidance for car owners. Diagnosis on the car can point to a different cause.