VOLVO
ECM-4801 - Three-way catalytic converter (TWC) efficiency. Permanent fault
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:
10 modelsC70 Cabriolet (1998–2005), C70 Coupé (1998–2002), S60 (2001–2009), S70 (1997–2000), S80 (1999–2006), V70 (1997–2000), V70 (2000–2008), V70 XC (1998–2000), V70 XC / XC70 (2001–2007), XC90 (2003–)
Show models by year and engine (26)
- Volvo C70 Cabriolet (1998–2005)1999, 2001–2005
- Volvo C70 Cabriolet (1998–2005)2000All engines except: B5244S
- Volvo C70 Coupé (1998–2002)1999All engines except: B5254S DENSO
- Volvo C70 Coupé (1998–2002)2000All engines except: B5244S
- Volvo C70 Coupé (1998–2002)2001–2002
- Volvo S60 (2001–2009)2001All engines except: B5244S, B5244S2, D5244T
- Volvo S60 (2001–2009)2002Engine B5204T5, B5234T3, B5234T7, B5244T3 only
- Volvo S60 (2001–2009)2003Engine B5204T5, B5234T3, B5234T7, B5244T3, B5254T2 only
- Volvo S60 (2001–2009)2004Engine B5204T5, B5234T3, B5234T7, B5254T2, B5254T4 only
- Volvo S70 (1997–2000)1999Engine B5204T3, B5204T4, B5234T3, B5234T7, B5254T only
- Volvo S70 (1997–2000)2000Engine B5204T3, B5204T4, B5234T3, B5234T7, B5244T only
- Volvo S80 (1999–2006)1999Engine B5204T3, B5204T4 only
- Volvo S80 (1999–2006)2000Engine B5204T3, B5204T4, B5204T5, B5234T7 only
- Volvo S80 (1999–2006)2001–2002Engine B5204T5, B5234T7, B5244T3 only
- Volvo S80 (1999–2006)2003Engine B5204T5, B5234T7, B5244T3, B5254T2 only
- Volvo S80 (1999–2006)2004Engine B5204T5, B5234T7, B5254T2 only
- Volvo V70 (1997–2000)1999Engine B5204T3, B5204T4, B5234T3, B5234T7, B5234T8, B5254T only
- Volvo V70 (1997–2000)2000All engines except: B5244S, B5244S2, B5244SG, B5244SG2, D5252T MSA 15.8
- Volvo V70 (2000–2008)2000All engines except: D5252T MSA 15.8
- Volvo V70 (2000–2008)2001–2002Engine B5204T5, B5234T3, B5234T7, B5244T3 only
- Volvo V70 (2000–2008)2003Engine B5204T5, B5234T3, B5234T7, B5244T3, B5254T2 only
- Volvo V70 (2000–2008)2004Engine B5204T5, B5234T3, B5234T7, B5254T2, B5254T4 only
- Volvo V70 XC (1998–2000)1999–2000
- Volvo V70 XC / XC70 (2001–2007)2001–2002
- Volvo V70 XC / XC70 (2001–2007)2003–2004All engines except: D5244T
- Volvo XC90 (2003–)2003–2004Engine B5254T2 only
What does this fault code mean?
The efficiency of the catalytic converter on bank 1 deviates too much, and the fault is still present when you read the code. The engine control module compares the signals from the oxygen sensors to check the converter, and the code is set when the deviation is too large.
Possible causes
- Misfiring in the engine
- Air leak in the intake system
- Air leak in the exhaust system
- Incorrect fuel pressure
- Uneven compression in the engine
- Defective catalytic converter
What you can do
- 1Read off and note the fault code, erase it and check whether it comes back straight away
- 2Check the intake system for air leaks such as cracks or loose hoses
- 3Look at the exhaust system for leaks at joints and seams
- 4A compression test and a check of fuel pressure need measurement, so have a workshop carry them out
- 5If none of this finds the cause, have a workshop decide whether the catalytic converter should be replaced
Symptoms you may notice1
- Emissions warning lamp (MIL) lit
What the fault can affect1
- Control of the rear oxygen sensor is switched off
General guidance for car owners. Diagnosis on the car can point to a different cause.