C0870Control Module Voltage Reference Output Circuit
- Generic OBD-II code · Chassis
- Can trigger limp mode
- How the car detects it
- C0870 is missing from the accessible J2012 code lists; it is documented at GM, where it covers the 5 V reference that a module feeds to its sensors. Saab workshop pages for the 2011 9-5 and 9-4X use it in the suspension control module, which feeds five acceleration sensors on the body and at the wheels: subcode 03 means that line is shorted to ground and 07 that it touches battery voltage, each for 1.5 s, checked between 9 and 16 V. Electronic damping then shuts off for the ignition cycle. The fix is to unplug the sensors one by one and watch the reference return to 4.8-5.2 V. Under the older name Device Voltage Reference Output 1 Circuit, GM hybrid pickups of 2005 and 2007 used it for the pedal sensor supply of the steering pump (above 4.65 V or below 3.95 V, type C, no MIL).
- What you may notice
- SERVICE SUSPENSION SYSTEM message
- Adaptive damping inactive for the rest of the trip
- Several acceleration sensor codes stored at once
- Likely causes
- LikelyOne acceleration sensor shorting the shared 5 V reference
- PossibleReference line chafed to ground or to battery voltage
- RareModule reference supply faulty, module replacement after wiring checks (Saab WIS)
- Repair
- Medium · Usually a job for a workshop.Typical cost: €80 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.