What it means
The second 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 B is the second monitored power rail for ECU-driven actuators. This code sets when the module detects that rail above its expected range, which can result from charging system overvoltage or a short to a higher-voltage wire.
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 check live actuator supply B voltage to see whether the high reading is present continuously or only during certain operating conditions.
- Check system charging voltage and related charging faults against the manufacturer's specification, since a regulator fault can raise multiple supply readings.
- Inspect the B rail wiring and connectors for damage or contact with a higher-voltage circuit, including signs of heat or corrosion.
- With the circuit isolated as directed by the manufacturer, test for a short between the B supply and nearby higher-voltage wiring.
- If the charging system and harness are sound, verify the module's B rail reading and connector condition using the manufacturer's diagnostic procedure.
Common fixes
- Repair a B supply wire shorted to a higher-voltage circuit.
- Repair corroded or damaged actuator supply B connector terminals.
- Repair the alternator regulator or other charging system fault if charging voltage exceeds the manufacturer's specification.
- Repair or replace the module only if its B rail input is inaccurate with correct external voltage.
Can I keep driving?
High supply voltage can cause actuators to behave abnormally and may damage electrical components if the overvoltage continues. Avoid unnecessary driving if charging voltage is high or the engine behaves erratically, and address the charging or wiring fault promptly.
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.