Powertrain, generic · Fuel and air metering (injector circuit)

P026A Charge Air Cooler Efficiency Below Threshold

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

P026A means the charge air cooler is not cooling enough. The module compares the temperature drop across the cooler with the maximum possible (inlet minus ambient) or with a model: GM's 6.6 litre LML diesel sets it below 25 % efficiency, later GM diesels below 50 %, both after two trips; Ford's 6.7 and 3.0 diesels when the measured temperature is 18–35 °C (3.0: 35–65 °C) off the model over about 10 s. GM's 3.0 twin-turbo petrol with a coolant-cooled charge air cooler sets it in the first trip when manifold air exceeds 110 °C or boost has been limited for a long time. Hot intake air costs power and raises NOx and soot.

Likely causes

Charge air cooler clogged on the outside (insects, leaves, dirt) or fins damaged
Coolant-cooled cooler: pump faulty, air in the low-temperature circuit, low coolant
Charge air or ambient temperature sensor inaccurate
Charge air cooler bypass stuck open
Software or calibration

Symptoms

  • Check engine light on
  • Loss of power under load or in heat
  • High intake air temperature in live data

Repair estimate

DifficultyMediumDIY possible
Parts and labour€50–900
Time0.5–3 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

charge air coolercharge air temperature sensorscharge air cooler coolant pump

Related codes

P007BP007CP026EP023AP024AP028A

References: law.cornell.edu, fordservicecontent.com, gsi.ext.gm.com, gsi.ext.gm.com.