VOLVO
ECM-B12A612 - Auxiliary Heater Water Pump. 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 (26)
- Volvo C30 (2007–2013)2011–2013Engine D4162T only
- Volvo S40 (2004–2013)2011–2012Engine D4162T only
- Volvo S60 (2011–)2011–2012Engine D4162T only
- Volvo S60 (2011–)2013Engine B5204T8, B5204T9, B5254T12, B5254T14, D4162T only
- Volvo S60 (2011–)2014–2015Engine B5204T8, B5204T9, B5254T12, B5254T14, D4162T, D4204T5 only
- Volvo S80 (2007–)2012Engine D4162T only
- Volvo S80 (2007–)2013Engine B5254T12, B5254T14, D4162T only
- Volvo S80 (2007–)2014Engine B5254T12, B5254T14, D4162T, D4204T5 only
- Volvo S80 (2007–)2015Engine D4162T, D4204T5 only
- Volvo V40 (2013–)2013All engines except: B4164T, B4164T3, D5204T4, D5204T6
- Volvo V40 (2013–)2014Engine B5204T8, B5204T9, B5254T12, B5254T14, D4162T only
- Volvo V40 (2013–)2015Engine B5204T8, B5204T9, D4162T, D4204T14 only
- Volvo V40 Cross Country (2013–)2013–2014All engines except: B4164T, D5204T4, D5204T6
- Volvo V40 Cross Country (2013–)2015All engines except: B4164T, B4204T11, D5204T6
- Volvo V50 (2004–2013)2011–2012Engine D4162T only
- Volvo V60 (2011–)2011–2012Engine D4162T only
- Volvo V60 (2011–)2013Engine B5204T8, B5204T9, D4162T, D82PHEV only
- Volvo V60 (2011–)2014Engine B5204T8, B5204T9, B5254T12, D4162T, D4204T5, D82PHEV only
- Volvo V60 (2011–)2015Engine B5204T9, B5254T12, D4162T, D4204T5, D82PHEV, D87PHEV only
- Volvo V60 Cross Country (2015–)2015
- Volvo V70 (2008–)2012Engine D4162T only
- Volvo V70 (2008–)2013Engine B5204T9, D4162T only
- Volvo V70 (2008–)2014–2015Engine B5204T9, D4162T, D4204T5 only
- Volvo XC60 (2009–)2014Engine D4204T5 only
- Volvo XC60 (2009–)2015Engine B5204T9, B5254T12, B5254T14, D4204T5 only
- Volvo XC70 (2008–)2014–2015Engine D4204T5 only
What does this fault code mean?
The engine control module monitors the coolant pump relay and activates it at regular intervals to check whether the fault has cleared itself. The code is set when the relay's connection to the module is short-circuited to supply voltage. The coolant pump is then switched off, which can affect temperature control and the parking heater.
Possible causes
- Loose connection or oxidation in the connector
- Signal wire short-circuited to supply voltage
- Damaged coolant pump relay
- Damaged pump
- Short circuit or open circuit in the wiring to the pump
What you can do
- 1Check that the relevant fuses are intact and that the connectors at the coolant pump relay are fully seated
- 2With a multimeter, check that the signal wire has no contact with battery voltage
- 3Check that the pump and its wiring are intact; a damaged pump or wire can produce the same effect
- 4If the connectors and wiring are sound, the relay or pump is probably damaged and should be replaced by a workshop
Symptoms you may notice4
- Uneven temperature in the cabin
- HYBRID drive mode is used all the time or too often, with the combustion engine running
- The parking heater does not work
- Text window with a warning symbol and text message
What the fault can affect2
- The coolant pump is switched off
- In cold outdoor weather the coolant pump keeps running
General guidance for car owners. Diagnosis on the car can point to a different cause.