Engine

P028C — Charge Air Cooler Cooling Fan Stuck On

Severity: low Safe to drive

What P028C means

The engine control unit switches the charge air cooler (intercooler) fan on through a relay or driver only when extra cooling is needed, such as when intake air temperature is high. P028C is set when the fan keeps running without a command from the ECM. Common causes are a stuck relay, a short in the control circuit, or a faulty fan motor or driver.

Symptoms

  • Intercooler fan runs constantly, even with the engine off
  • Check Engine light on
  • Unusual fan noise
  • Dead or weak battery after parking
  • Possible slight loss of performance or fuel economy

Possible causes

  1. Stuck relay with welded contacts
  2. Short to ground or to power in the fan control circuit
  3. Faulty fan motor or its built-in control module
  4. Incorrect signal from the charge air temperature sensor
  5. Corroded or damaged wiring and connectors
  6. Failed driver inside the ECM (uncommon)

How to diagnose

  1. Scan for all codes and review freeze frame data, looking for other boost or temperature codes
  2. Shut the engine off and see whether the fan keeps running
  3. Pull the fan relay: if the fan stops, replace the relay and inspect its terminals
  4. Inspect the fan wiring and connectors for chafing, moisture and corrosion
  5. Test the control circuit for a short to ground or to power
  6. Compare charge air temperature sensor readings with actual temperature
  7. Command the fan on and off with a scan tool's actuator test
  8. If everything checks out, evaluate the ECM and look for software updates

Common fixes

  • Replace the fan relay
  • Repair damaged wiring or connectors
  • Replace the charge air cooler fan assembly
  • Replace the charge air temperature sensor
  • Reflash or replace the ECM if confirmed faulty

Questions and answers

What does P028C mean?

It means the charge air cooler fan is running when the ECM has not commanded it. The usual culprits are a stuck relay, wiring faults or a bad fan.

Can I drive with P028C?

Usually yes, for a short time. The fan may keep running after shutdown and drain the battery, so don't put the repair off.

How do I quickly find the cause of P028C?

Pull the fan relay. If the fan stops, the relay or its control circuit is at fault. If it keeps running, check the wiring for a short and test the fan itself.

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.