Chassis, generic

C0317 Compressor Relay Circuit

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

C0317 is publicly undocumented: it is missing from every publicly available J2012 list, from GM's keyword bulletin PIP5094 and from the whole NHTSA bulletin index. What follows describes only the part named in the title. On air or self-levelling suspension a relay carries the heavy compressor current and is energised by the suspension module. Land Rover ships the compressor relay together with the replacement compressor for the 2010 Range Rover, whose compressor could fail by running too long. Audi has technicians open relay J403 of the self-levelling compressor on A6 and Q7 models and judge its contacts: burnt contacts mean compressor and relay are both renewed. Volvo checks fuse and relay before it blames the compressor. A circuit fault here leaves the vehicle unable to raise or hold its ride height.

Likely causes

Relay contacts burnt or welded by a compressor drawing too much current
Open or shorted control line between suspension module and relay coil
Worn or seized compressor overloading the relay
Blown compressor fuse or corroded relay socket

Symptoms

  • Suspension warning or air suspension fault message
  • Vehicle sits low and does not rise
  • Compressor runs constantly or never starts

Repair estimate

DifficultyMediumDIY possible
Parts and labour€20–1,200
Time0.3–3 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

compressor relayair compressorair suspension modulerelay wiring

Related codes

C0301C0312

References: static.nhtsa.gov, static.nhtsa.gov, static.nhtsa.gov.