Fuel and air

P023A — Charge Air Cooler Coolant Pump Control Circuit Open

Severity: medium Drive with care, to a shop

What P023A means

On engines with a liquid-cooled charge air cooler (intercooler), the engine control module runs an electric coolant pump that circulates coolant through it. When the ECM sees an open circuit or no load on the pump control line, it sets P023A and turns on the check engine light. Without the pump, intake air is cooled poorly.

Symptoms

  • Check engine light on
  • Reduced power and sluggish acceleration under load
  • Higher intake air temperatures
  • Possible overheating under sustained boost
  • Limp mode or limited boost

Possible causes

  1. Open or damaged wiring in the pump control circuit
  2. Failed charge air cooler coolant pump
  3. Blown fuse or faulty pump relay
  4. Corroded or loose connector terminals
  5. ECM fault (uncommon)

How to diagnose

  1. Scan all codes and freeze frame data, then clear the code and see if it returns
  2. Inspect the pump fuse and relay, and swap the relay with a known good one
  3. Check the pump and ECM connectors for corrosion, moisture or bent pins
  4. Test for power and ground at the pump connector with a multimeter
  5. Check the control wire from the ECM to the pump for opens and shorts
  6. Command the pump on with a scan tool and confirm it runs
  7. Check the coolant level and look for air in the intercooler loop
  8. Suspect the ECM only after everything else checks out

Common fixes

  • Repair the wiring or replace a damaged connector
  • Replace the fuse or relay
  • Replace the charge air cooler coolant pump
  • Bleed the intercooler coolant loop after repairs
  • Reprogram or replace the ECM (last resort)

Questions and answers

What does P023A mean?

The ECM detected an open circuit in the control line of the charge air cooler coolant pump. Wiring, a connector, the fuse or relay, or the pump itself are the usual culprits.

Can I drive with P023A?

Short trips at moderate load are usually possible, but power may drop and the engine tolerates boost poorly. Don't put off the repair.

How much does it cost to fix P023A?

It depends on the cause: a fuse or relay is cheap, while a new pump or a wiring harness repair costs more. Test the circuit first to find out.

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.