Engine

P023C — Charge Air Cooler Coolant Pump Control Circuit High

Severity: medium Drive with care, to a shop

What P023C means

The engine control module detected excessive voltage in the control circuit of the electric pump that moves coolant through the liquid-cooled charge air cooler (intercooler). This system lowers the temperature of the air leaving the turbo or supercharger. When the circuit doesn't behave as expected, the module can't control the pump properly and sets the code.

Symptoms

  • Check Engine light on
  • Reduced power or sluggish acceleration
  • Higher than normal intake air temperature on a scan tool
  • Worse fuel economy
  • Limited boost or reduced-power mode

Possible causes

  1. Failed charge air cooler coolant pump
  2. Wiring shorted to voltage, or chafed or damaged harness
  3. Corroded or loose pump connector terminals
  4. Stuck or faulty pump relay
  5. Faulty engine control module (rare)

How to diagnose

  1. Read all codes and freeze frame data, and note the intake air temperature
  2. Inspect the pump connector and harness for chafing, melting or corrosion
  3. Check the pump fuse and relay, and swap in a known good relay if in doubt
  4. Measure supply voltage and control signal at the pump connector with a multimeter
  5. Test the control circuit for a short to voltage and check the ground path
  6. Command the pump on with a scan tool and confirm it runs and coolant circulates
  7. Check the coolant level in the intercooler loop and look for air pockets
  8. If everything checks out, test the control module and look for software updates

Common fixes

  • Replace the charge air cooler coolant pump
  • Repair or replace damaged wiring and connectors
  • Replace the faulty pump relay
  • Top off and bleed the intercooler coolant loop
  • Reflash or replace the control module as a last resort

Questions and answers

What does P023C mean?

It means high voltage in the control circuit of the charge air cooler coolant pump. The usual culprits are the pump itself, a wiring short to voltage, or the relay.

Can I drive with code P023C?

Briefly and gently, yes, but avoid heavy loads. Hot intake air reduces power and raises the chance of knock, so don't put the repair off.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.