Engine

P026A — Charge Air Cooler Efficiency Below Threshold

Severity: medium Drive with care, to a shop

What P026A means

The engine control module compares the temperature of the air leaving the intercooler with intake temperature and an expected model. If the air compressed by the turbo or supercharger is not cooled as much as it should be, P026A is set. The cause can be a truly underperforming cooler or a misreading temperature sensor.

Symptoms

  • Check Engine light on
  • Reduced power and sluggish acceleration
  • Worse fuel economy
  • Rough idle or hesitation under load
  • Limp mode under heavy throttle

Possible causes

  1. Clogged intercooler fins (dirt outside, oil inside)
  2. Faulty or dirty charge air temperature sensor
  3. Cracked or loose boost hoses, clamps or pipes causing leaks
  4. Bent intercooler fins or blocked airflow to the cooler
  5. Low coolant or failed fan/pump on liquid-cooled intercoolers
  6. ECM software issue (uncommon)

How to diagnose

  1. Scan all codes and freeze frame data, and look for related boost or temperature sensor codes
  2. Inspect the intercooler and the airflow in front of it for debris or bent fins
  3. Check hoses, clamps and pipes for cracks, oil traces and leaks
  4. Compare charge air and intake air temperature readings on a cold engine; they should be close
  5. Inspect the sensor connector and wiring, and test the sensor resistance
  6. On liquid-cooled systems, check coolant level, pump and fan operation
  7. Smoke or pressure test the intake and boost system for leaks
  8. Check for ECM software updates

Common fixes

  • Clean or replace the intercooler
  • Replace the faulty charge air temperature sensor
  • Replace damaged hoses and clamps and fix boost leaks
  • Restore cooling system function: top up coolant, replace the fan or pump
  • Update the ECM software if the manufacturer offers it

Questions and answers

What does P026A mean?

The ECM has detected that the charge air cooler is not cooling the intake air as well as expected. The problem may be in the intercooler, the piping or the temperature sensor.

Can I drive with P026A?

For a short time, yes, but expect reduced power. Driving long with hot intake air increases knock risk, so get it diagnosed soon.

How do I clear P026A?

You can clear it with a scan tool, but it will return unless the cause is fixed. Start by checking the intercooler, hoses and temperature sensor.

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.