VOLVO
AEM-7A12 - Rheostat signal. Signal too low / high or signal missing. Permanent fault
System
Accessory Electronic Module (AEM)
Volvo models this fault code applies to
Applies to the following models:
4 modelsS60 (2001–2009), S80 (1999–2006), V70 (2000–2008), V70 XC / XC70 (2001–2007)
Show models by year and engine (4)
What does this fault code mean?
The AEM has registered a signal that is too low or too high, or a break, on the rheostat wire to the radio, and the fault is permanent. The rheostat function on the audio system does not work. The wire may be shorted to ground or supply voltage, or have a break, and the radio may be faulty.
Possible causes
- Rheostat wire to the radio shorted to ground
- Rheostat wire to the radio shorted to supply voltage
- Break in the rheostat wire to the radio
- Faulty radio
What you can do
- 1Follow the rheostat wire to the radio and look for chafing or damage that could cause a short or a break
- 2Check the connectors at the radio for oxidation and loose connections
- 3If the fault remains, have the radio replaced by a workshop after checking the wire
Symptoms you may notice1
- The rheostat function on the audio system does not work
General guidance for car owners. Diagnosis on the car can point to a different cause.