Powertrain, generic (extended)

P2CAF Charge Air Cooler Coolant Pump B Control Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P2CAF says the control line of charge air cooler pump B is tied to supply voltage, so the engine computer cannot pull it down when it switches the pump on. As with the rest of the pump B series, no manufacturer documents the code publicly. For pump A, GM's LT5 table 19OBDG03A (P023C) carries out this check while the driver is on: below 0.5 Ω between output and controller power counts as a short to power, 50 of 63 samples, Type A with MIL in the first trip. Because the driver may shut itself down to avoid overheating, pump B then usually stops and the second half of the cooling loop loses flow. Typical causes are a wire pinched against a 12 V feed, moisture bridging two pins, or a shorted pump. A short to ground is P2CAE, an open line P2CAD.

Likely causes

Control wire of pump B pinched against a 12 V feed
Moisture bridging supply and control pins at the pump
Shorted electronics inside pump B

Symptoms

  • MIL on after the first faulty trip
  • Pump B does not start when commanded
  • Reduced power at high load

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€30–700
Time0.5–3 h

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

Parts involved

cac coolant pump bwiring harnessecm

Related codes

P2CADP2CAEP023CP2CB4

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