What it means
The module monitors voltage in circuit A associated with the A/C compressor motor. It sets this code when the reported voltage rises above the expected range.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Circuit A carries voltage associated with the electric A/C compressor motor, which the module monitors during compressor operation. This code sets when the reported voltage exceeds the expected range; an overcharging alternator or drifting voltage regulator can raise the supply.
Common causes
Most likely first.
- Alternator overvoltage
- Voltage regulator drifted
How to diagnose it
- Save freeze-frame data and check circuit A voltage live to confirm the high reading and when it occurs.
- Check battery and charging-system voltage under the conditions in the freeze frame and compare it with the manufacturer’s specification.
- Inspect circuit A wiring and connectors for a short to a higher-voltage feed, incorrect repairs, or damaged insulation.
- Test the alternator and voltage regulator output according to the manufacturer’s service information.
- If charging output and wiring are normal, test the compressor circuit and voltage input path for a misleading reading.
Common fixes
- Repair a circuit A wire shorted to a higher-voltage feed.
- Correct a charging-system overvoltage if confirmed by testing.
- Repair or replace the voltage regulator if it fails the specified test.
- Repair connector or circuit faults that cause the module to see an incorrect voltage.
Can I keep driving?
The code may cause the module to restrict or shut off the electric A/C compressor. If charging-system overvoltage is present, avoid unnecessary driving and have it checked promptly because excessive system voltage can damage electrical components.
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.