What it means
The third actuator supply rail is open. All loads on this rail are powerless and report follow-on faults.
At a glance
- Usually lights the check-engine light
How it works
Actuator supply voltage C is a shared power feed for actuators connected to that rail. The control module detects that the feed is open, so the affected actuators may lose power and generate additional fault codes.
Common causes
Most likely first.
- Blown fuse on the supply rail
- Broken supply wire from main relay
Symptoms
- Check-engine light
- One or more actuators may not operate
How to diagnose it
- Scan for related actuator codes and identify which components are supplied by rail C before testing the shared feed.
- Check the rail C fuse and relay, then inspect their sockets for heat damage or poor terminal contact.
- Inspect the supply wiring from the main relay to the rail C loads for breaks, loose connectors, or corrosion.
- Check continuity through the supply path and verify power at the affected actuator connectors using the manufacturer's wiring information.
- If the fuse, wiring, and connections are intact, test the relay and control module feed according to the manufacturer's procedure.
Common fixes
- Replace a blown rail C fuse after checking for a cause of the overload.
- Repair a broken supply wire between the main relay and rail C.
- Repair loose or corroded relay, fuse-box, or actuator terminals.
- Replace a faulty supply relay if testing confirms it has failed.
Can I keep driving?
Driving may be unreliable if rail C powers an engine actuator needed for normal operation; avoid long trips and hard acceleration. Stop if the engine loses power, runs poorly, or displays a temperature or other urgent warning.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.