What it means
The ECM detects a high fault on the a/c compressor motor voltage sensor a circuit. Reading cannot be used reliably for control.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Voltage sensor A reports electric A/C compressor motor voltage to the control module. This code sets when the sensor circuit signal is higher than the module’s expected range, which can happen with a short to power, an open sensor, or a poor connection.
Common causes
Most likely first.
- Signal wire shorted to B+
- Open sensor
- Connector pins corroded - high contact resistance
Symptoms
- A/C warning light may come on
- Air conditioning may provide little or no cooling
- A/C operation may be limited or disabled
How to diagnose it
- Capture freeze-frame data and check sensor A voltage live to confirm that the signal is high and note whether the compressor was operating.
- Inspect sensor A’s connector and harness for corrosion, pushed-back pins, damaged insulation, and contact with a power feed.
- Using the wiring diagram, check the signal wire for a short to battery voltage and verify sensor power and ground connections.
- With the circuit isolated as directed by the manufacturer, check continuity and connector contact resistance to find opens or poor connections.
- If wiring and terminals pass, test voltage sensor A against the manufacturer’s specification and replace it only if it fails.
Common fixes
- Repair a signal wire shorted to a power feed.
- Clean, tighten, or replace corroded or damaged connector terminals.
- Repair an open or damaged section of sensor wiring.
- Replace voltage sensor A if it remains open or produces an out-of-range signal after circuit repairs.
Can I keep driving?
The module may restrict or shut off the electric A/C compressor, so cooling can be reduced or absent. Driving is generally possible if the vehicle otherwise operates normally, but resolve the fault soon and use another way to keep the windshield clear.
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.