What it means
The third actuator supply rail is above the expected voltage. Likely a charging system overvoltage or a short to a higher-voltage source.
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. This code sets when the control module detects voltage above the allowed range, which can result from charging-system overvoltage or a connection to a higher-voltage circuit.
Common causes
Most likely first.
- Alternator regulator failure
- Wiring shorted to a higher-voltage circuit
- Connector pins corroded - high contact resistance
Symptoms
- Check-engine light
- One or more actuators may operate abnormally
How to diagnose it
- Record freeze-frame data and scan for related actuator codes to identify the conditions when rail C voltage rises.
- Check charging-system data and battery voltage for evidence of an overcharging condition.
- Inspect rail C wiring and connectors for damage, incorrect repairs, or contact with a higher-voltage circuit.
- Measure the supply at the rail C feed and affected actuator connectors, comparing readings with the manufacturer's specification.
- If charging and wiring are normal, check the relay and control module circuit using the manufacturer's diagnostic procedure.
Common fixes
- Repair a rail C wire shorted to a higher-voltage source.
- Repair poor or corroded connections affecting the supply circuit.
- Repair the charging-system regulator if testing confirms overvoltage.
- Replace a faulty relay or repair a control module circuit only when tests identify it as the cause.
Can I keep driving?
Avoid unnecessary driving until the high supply voltage is checked, since overvoltage can damage actuators and other electrical components. Stop if additional electrical warnings or abnormal engine operation appear.
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.