VOLVO
ECM-0024 - Auxiliary heater relay 1+2. Auxiliary heater 2, signal too low. Intermittent fault.
System
Engine Control Module (ECM)
Volvo models this fault code applies to
Applies to the following models:
3 modelsS70 (1997–2000), V70 (1997–2000), V70 (2000–2008)
What does this fault code mean?
The engine control module has received too low a signal from auxiliary heater relay 2, and the fault is intermittent, meaning it comes and goes. The fault can mean the auxiliary heater does not warm the cabin when it is needed. The code only concerns the second auxiliary heater and its relay.
Possible causes
- The signal wire to auxiliary heater relay 2 is shorted to earth
- Break in the signal wire to auxiliary heater relay 2
- Faulty relay for auxiliary heater 2
- Contact resistance in the connections
What you can do
- 1Check the wires and connectors to the auxiliary heater relay for play, chafing and corrosion
- 2Check the auxiliary heater relay and its socket for contact resistance and oxidation
- 3Check that the fuses for the auxiliary heaters are intact. Their location is in the owner's manual or the fuse list
- 4Measure with a multimeter that the signal wire to the relay is not shorted to earth and has no break
- 5Clear the fault code and road test the car. If it returns, have a workshop investigate the relay and the auxiliary heater
Symptoms you may notice1
- Poor heating in the cabin
What the fault can affect1
- The auxiliary heaters are switched off
General guidance for car owners. Diagnosis on the car can point to a different cause.