ECM-400C - Three-way catalytic converter (TWC) efficiency, bank 1. Signal too high
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:
9 modelsC30 (2007–2013), C70 (2006–2013), S40 (2004–2013), S60 (2001–2009), S80 (1999–2006), V50 (2004–2013), V70 (2000–2008), V70 XC / XC70 (2001–2007), XC90 (2003–)
Show models by year and engine (18)
- Volvo C30 (2007–2013)2007Engine B5254T3 only
- Volvo C70 (2006–2013)2006–2007Engine B5254T3 only
- Volvo S40 (2004–2013)2005–2007Engine B5254T3 only
- Volvo S60 (2001–2009)2005–2006Engine B5204T5, B5244T4, B5244T5, B5254T2, B5254T4 only
- Volvo S60 (2001–2009)2007Engine B5204T5, B5244T5, B5254T2, B5254T4 only
- Volvo S60 (2001–2009)2008–2009Engine B5204T5, B5244T5, B5254T2 only
- Volvo S80 (1999–2006)2005–2006Engine B5204T5, B5244T4, B5254T2, B6294S2, B6294T only
- Volvo V50 (2004–2013)2005–2007Engine B5254T3 only
- Volvo V70 (2000–2008)2005Engine B5204T5, B5244T4, B5244T5, B5254T2, B5254T4 only
- Volvo V70 (2000–2008)2006–2007Engine B5204T5, B5244T5, B5254T2, B5254T4 only
- Volvo V70 (2000–2008)2008Engine B5254T2 only
- Volvo V70 XC / XC70 (2001–2007)2005All engines except: D5244T
- Volvo V70 XC / XC70 (2001–2007)2006Engine B5244T4, B5254T2 only
- Volvo V70 XC / XC70 (2001–2007)2007Engine B5254T2 only
- Volvo XC90 (2003–)2005–2006Engine B5254T2, B6294T only
- Volvo XC90 (2003–)2007–2012Engine B5254T2 only
- Volvo XC90 (2003–)2013–2014Engine B5254T9 only
- Volvo XC90 (2003–)2015
What does this fault code mean?
The efficiency of the catalytic converter on bank 1 deviates too much, according to the engine control module. It compares the signal from the rear oxygen sensor with the front one, and when the difference becomes too large the code is set while driving. The cause may be misfiring, a leak in the intake or exhaust system, faulty fuel pressure, uneven compression or a damaged catalytic converter.
Possible causes
- Misfiring
- Leakage in the intake system
- Leakage in the exhaust system
- Faulty fuel pressure
- Uneven compression
- Damaged catalytic converter
What you can do
- 1First check whether there are codes for misfiring, and deal with those before this one
- 2Check the spark plugs for damage to the insulation, since misfiring can cause the same fault
- 3Look for leaks in the intake system and the exhaust system, for example at hoses, joints and gaskets
- 4Have a workshop check fuel pressure, residual pressure and compression with diagnostic equipment
- 5If the fault remains after this: have a workshop try a new oxygen sensor and then a new catalytic converter
Symptoms you may notice1
- Malfunction indicator lamp is lit
What the fault can affect2
- Rear oxygen sensor control is switched off
- Rear long-term fuel trim is disabled
General guidance for car owners. Diagnosis on the car can point to a different cause.