VOLVO
ECM-0426 - Front temperature sensor, catalytic converter. Faulty signal
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 engine control module (ECM) continuously compares the signal from the front temperature sensor in the catalytic converter with a calculated value. If they do not match, the fault is set, and the check is made when the ignition is switched on. The causes are poor contact in the connections, an open or shorted wiring fault to the sensor, or a damaged temperature sensor.
Possible causes
- Poor contact, contact resistance or oxidation at the sensor terminals
- Open circuit or short circuit in the wiring to the temperature sensor
- Damaged temperature sensor
What you can do
- 1Switch off the ignition and check the connector to the front temperature sensor in the converter for looseness, contact resistance and oxidation
- 2Look for damage on the sensor wiring, especially where it runs close to the exhaust pipe and may have chafed
- 3Use a multimeter to check that the signal wire to the sensor has no open circuit or short circuit
- 4Also use a multimeter to check that the supply wire to the sensor has no open circuit or short circuit
- 5If you have a diagnostic tool, compare the front sensor temperature with the rear one in live data after a drive and check that they rise at about the same time
- 6If the fault remains, have a workshop with diagnostic equipment check and, if needed, replace the 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.