VOLVO
ECM-B139F12 - Main Battery Relay. General Electrical Failures. Circuit short to battery
System
Engine Control Module (ECM)
Volvo models this fault code applies to
Applies to the following models:
12 modelsC30 (2007–2013), S40 (2004–2013), S60 (2011–), S80 (2007–), V40 (2013–), V40 Cross Country (2013–), V50 (2004–2013), V60 (2011–), V60 Cross Country (2015–), V70 (2008–), XC60 (2009–), XC70 (2008–)
Show models by year and engine (24)
- Volvo C30 (2007–2013)2011–2013Engine D4162T only
- Volvo S40 (2004–2013)2011–2012Engine D4162T only
- Volvo S60 (2011–)2011Engine B4164T, B4164T3, D4162T only
- Volvo S60 (2011–)2012All engines except: B4204T7, B5254T5, B6304T4
- Volvo S60 (2011–)2013–2014All engines except: B4204T7, B6304T4
- Volvo S60 (2011–)2015All engines except: B6304T3, B6304T4, B6304T5
- Volvo S80 (2007–)2011Engine B4164T only
- Volvo S80 (2007–)2012Engine B4164T, B4164T2, D4162T, D5204T3, D5244T11, D5244T15 only
- Volvo S80 (2007–)2013–2014All engines except: B4204T6, B4204T7, B6304T4, B6324S4, B6324S5
- Volvo S80 (2007–)2015All engines except: B6304T4, B6324S4, B6324S5
- Volvo V40 (2013–)2013–2015
- Volvo V40 Cross Country (2013–)2013–2015
- Volvo V50 (2004–2013)2011–2012Engine D4162T only
- Volvo V60 (2011–)2011Engine B4164T, B4164T3, D4162T only
- Volvo V60 (2011–)2012–2014All engines except: B4204T7, B6304T4
- Volvo V60 (2011–)2015All engines except: B6304T3, B6304T4, B6304T5
- Volvo V60 Cross Country (2015–)2015
- Volvo V70 (2008–)2011Engine B4164T only
- Volvo V70 (2008–)2012All engines except: B4204T7, B5254T10, B6304T4, B6324S5
- Volvo V70 (2008–)2013–2014All engines except: B4204T7, B6304T4, B6324S5
- Volvo V70 (2008–)2015All engines except: B6304T4
- Volvo XC60 (2009–)2012Engine D5204T3, D5244T11, D5244T15, D5244T17 only
- Volvo XC60 (2009–)2013–2015All engines except: B4204T7, B6304T4, B6324S4, B6324S5
- Volvo XC70 (2008–)2012–2015All engines except: B6304T4, B6324S4, B6324S5
What does this fault code mean?
The engine control module sees that the signal cable to the main battery relay has contact with voltage instead of being controlled as intended. The relay may then not switch in and out correctly, and the automatic start/stop function is switched off. The fault can also stop the engine from starting.
Possible causes
- Loose connector or oxidation in the connector
- Signal cable short-circuited to supply voltage (positive)
- Damaged battery relay
- Mechanical or electrical fault on the relay
- Wiring to the relay is shorted or broken
What you can do
- 1Check that the fuses are intact
- 2Check that the battery terminals are tight and that the battery is charged
- 3Look for wires touching the battery positive terminal or another live wire where the insulation is worn or pinched
- 4Check the connectors at the relay and the engine control module for play and corrosion
- 5Erase the fault code and road test the car to see whether the fault returns
- 6If the fault remains after these checks, have a workshop replace the battery relay
Symptoms you may notice2
- Automatic engine start/stop does not work, both while driving and at idle
- The engine does not start, the starter motor does not turn and there is no clicking sound at start attempts
What the fault can affect2
- The automatic engine start/stop function is switched off
- Starting can be prevented when the relay does not work
General guidance for car owners. Diagnosis on the car can point to a different cause.