P023C
Charge Air Cooler Coolant Pump A Control Circuit High.
- Generic
- Powertrain
- Generic code
- Medium severity
How this code is built
- P
- SystemPowertrain
- 0
- Defined bySAE, the same on every car
- 2
- AreaFuel and air metering (injector circuit)
- 3C
- FaultThe specific fault in that area
What it means
P023C means the engine control unit has detected a high voltage or high signal state on the control circuit for charge air cooler coolant pump A, which circulates coolant through a water-cooled intercooler. The control unit compares the commanded pump state with the signal it sees on the circuit, and the two do not agree. This is often an open circuit, short to voltage or a fault within the pump driver. Exact circuit layout and pump control method depend on the vehicle.
Symptoms
- Engine warning light on
- Reduced engine power or limp mode in some cases
- Higher intake air temperatures, especially in hot weather or under load
- Poor performance or hesitation when towing or accelerating hard
- Possible whining or no noise from the pump, or pump running constantly
Possible causes
- Faulty charge air cooler coolant pump (internal electrical fault or failed driver)likely
- Damaged, chafed or corroded wiring in the pump control circuit (open circuit or short to voltage)likely
- Poor connection at the pump or control unit connector, such as corrosion, bent pins or water ingresslikely
- Blown fuse or faulty relay in the pump supply or control circuit, depending on the vehiclepossible
- Low coolant level or air in the intercooler circuit causing the pump to be operated abnormallypossible
- Fault in the engine control unit output driverrare
- Outdated control unit software where the manufacturer has issued a known fixrare
How to diagnose
- Read all stored and pending codes and record the freeze frame data, noting engine temperature, load and ambient conditions.
- Check the coolant level in the intercooler circuit and the main system, and look for leaks around the pump, hoses and cooler.
- Visually inspect the pump wiring, connector and fuse or relay for damage, corrosion, heat damage or water ingress.
- Listen and feel for pump operation with the ignition on or engine running, and use a scan tool's actuator test if the vehicle supports it.
- Check the supply voltage, earth and control signal at the pump connector against the manufacturer's wiring diagram.
- Test the wiring for continuity and shorts to voltage between the pump and the control unit with the connectors disconnected.
- Check the relay and fuse operation, then test the pump itself as the manufacturer specifies.
- Check for relevant software updates or technical bulletins for the specific model and engine.
How to fix
- Replace the charge air cooler coolant pump if it is faulty.
- Repair or replace damaged wiring and clean or renew corroded or damaged connectors.
- Replace a blown fuse only after finding the cause, and renew a faulty relay.
- Top up and bleed the intercooler coolant circuit following the manufacturer's procedure and fix any leak.
- Update the control unit software if a known fault is documented, or repair or replace the control unit only after all other causes are ruled out.
Can I keep driving?
The car can usually be driven for a short time, but boost may be limited and the intake air may run hot, so book it in soon. Avoid heavy loads, towing and hard acceleration until it is fixed, and stop if the engine overheats or a coolant warning appears.
Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.