Engine

P028E — Charge Air Cooler Cooling Fan Control Circuit High

Severity: medium Drive with care, to a shop

What P028E means

The engine control module runs the charge air cooler (intercooler) fan and monitors the voltage in its control circuit. P028E is set when that voltage is higher than expected, for example from a short to voltage, a faulty relay, or a bad control module. The fan may then fail to run properly, and the intake air is cooled less effectively.

Symptoms

  • Check Engine light is on
  • Reduced power under load
  • Intercooler fan does not run or runs constantly
  • Higher than normal intake air temperature
  • Engine may enter limp mode

Possible causes

  1. Wiring harness fault such as a short to voltage or an open circuit
  2. Failed charge air cooler fan motor
  3. Faulty fan relay or control module
  4. Corroded or damaged connector terminals
  5. ECM fault (uncommon)
  6. Software issue or a different code definition on some models

How to diagnose

  1. Read all codes and freeze frame data and look for related intake temperature or boost codes
  2. Inspect the fan, connectors, and harness for damage, heat marks, and corrosion
  3. Check the fan fuse and relay
  4. Command the fan on with a scan tool using active tests
  5. Measure voltage and resistance in the control circuit to find a short to voltage or an open
  6. Check power and ground at the fan connector
  7. Test the fan motor itself by applying power directly
  8. Check for ECM software updates before suspecting the module

Common fixes

  • Repair the wiring harness and connectors
  • Replace the charge air cooler fan
  • Replace the fan relay or control module
  • Reflash or replace the ECM only if everything else checks out

Questions and answers

What does P028E mean?

It means the ECM detected a high signal in the charge air cooler fan control circuit. The usual causes are wiring, a relay, or the fan itself.

Can I drive with code P028E?

For a short time, if you keep the engine load light. Poor intercooling reduces power, so get it diagnosed soon.

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.