VOLVO
ECM-151B - Idle Speed Control - RPM Lower Than Expected
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 (5)
- 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)2008–2010Engine D4204T only · Transmission MMT6, MPS6 only
- Volvo V50 (2004–2013)2008–2010Engine D4204T only · Transmission MMT6, MPS6 only
What does this fault code mean?
The ECM keeps watch over the idle control, meaning how steadily the engine holds its speed when the car stands still. If idle speed is lower than expected, fault code ECM-151B is set. Common causes are a blocked fuel filter or low fuel pressure, which leave the engine with too little fuel at idle.
Possible causes
- Blocked fuel filter
- Low fuel pressure
What you can do
- 1Check that the fuses for the engine control module and the fuel pump are intact; the fuse locations are often on the inside of the fuse box cover
- 2An old or clogged fuel filter can cause low fuel pressure. Have a workshop replace it if it is old
- 3If you have a diagnostic tool: activate the fuel pump and listen for it to start
- 4Clear the fault code and check whether it comes back after the engine has idled for a while
- 5If the fault remains, have a workshop measure the fuel pressure and check the fuel system
Symptoms you may notice2
- Low idle, the engine runs slower than usual when the car is standing still
- The fault may show all the time or only now and then
General guidance for car owners. Diagnosis on the car can point to a different cause.