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

P023B Charge Air Cooler Coolant Pump A Control Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

Some engines cool the charge air with a coolant-to-air cooler in its own low-temperature circuit, driven by an electric pump – GM uses this on supercharged V8s such as the LT4 (Camaro ZL1, Corvette Z06, CTS-V) and LT5 (Corvette ZR1). P023B means GM's driver diagnosis has found a short to ground (0.5 Ω or less between output and ground with the driver off). Bundled conditions: main relay at least 11 V, ignition above 5 V; 50 of 63 samples set the code with the warning light in the first trip on 2018–2019 engines, older modules need two trips. Without the pump the charge air gets hot and boost is limited.

Likely causes

Control wire to the pump shorted to ground
Pump shorted internally
Moisture or corrosion in the connector
Driver stage in the engine module faulty

Symptoms

  • Check engine light on
  • Loss of power under load or in heat (boost limited)
  • Follow-up code P026A possible

Repair estimate

DifficultyMediumDIY possible
Parts and labour€30–450
Time0.5–2 h

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

Parts involved

charge air cooler coolant pumppump wiringengine control module

Related codes

P023AP023CP026AP026E

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