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

P028D Charge Air Cooler Cooling Fan Control Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

Some vehicles – mainly commercial and off-road machines, or cars with a separate cooler for a coolant-cooled charge air cooler – have their own fan for the charge air cooler, switched by the engine module; a Deere patent describes such a fan that is also reversed to blow out dirt. P028D means the fan's control circuit reads low – typically the control wire shorted to ground, detected by the driver stage. Depending on whether the module switches the low or the high side, the fan then runs permanently or not at all. No manufacturer document using this code was found; the description rests on CARB's output component requirement.

Likely causes

Control wire shorted to ground (chafing)
Relay coil or fan module input shorted
Moisture or corrosion in the connector
Driver stage in the engine module faulty

Symptoms

  • Warning light (manufacturer-dependent)
  • Fan runs permanently or not at all
  • Loss of power in heat possible

Repair estimate

DifficultyMediumDIY possible
Parts and labour€30–300
Time0.5–2 h

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

Parts involved

charge air cooler fanfan relayfan wiring

Related codes

P028AP028BP028CP028EP028FP026A

References: law.cornell.edu, patents.google.com.