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 falls below 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, and the module monitors it to decide whether compressor operation is within range. This code sets when the reported circuit voltage is too low, which can result from low supply voltage under load or excess resistance in the wiring.
Common causes
Most likely first.
- Supply voltage low under load
- High wiring resistance
How to diagnose it
- Record freeze-frame data and compare circuit A voltage live with the compressor off and commanded on to see whether it falls under load.
- Check battery and charging-system data for low system voltage during the conditions shown in the freeze frame.
- Inspect circuit A’s wiring, connectors, and grounds for corrosion, looseness, heat damage, or an undersized or damaged repair.
- Measure voltage drop across the circuit and its connections under load, following the wiring diagram and comparing results with the manufacturer’s specification.
- If supply and wiring pass, test the compressor and its control circuit using the manufacturer’s diagnostic procedure.
Common fixes
- Clean and secure circuit A terminals and ground connections.
- Repair high-resistance or damaged wiring in circuit A.
- Correct a low charging-system supply if testing confirms it.
- Repair the compressor or control component only if further testing identifies it as the source of the low reading.
Can I keep driving?
The module may limit or disable the electric A/C compressor, reducing or eliminating cabin cooling. Driving is generally possible if the vehicle has no other electrical or drivability symptoms, but investigate promptly because an underlying low-voltage supply can affect other systems.
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.