What Does P023C Mean?
The charge air cooler coolant pump control circuit is reading higher voltage than expected. The ECM has detected that the signal voltage on the pump control wire exceeds the normal operating range. This can prevent the intercooler coolant pump from functioning correctly, resulting in hotter intake air temperatures and potentially reduced engine performance under boost.
Common Causes
30%
Short to voltage in the pump control circuit wiring
30%
Faulty charge air cooler coolant pump with internal short
20%
Defective pump relay stuck in the closed position
15%
ECM driver circuit failure for pump control
5%
Corroded connector causing high-resistance feedback
Diagnostic Steps
1
Review freeze frame data and note operating conditions — compare intake air temperature with ambient temperature to determine if the charge air cooler is functioning at all.
2
Inspect the pump connector and wiring for damage, chafing, or signs of wiring rubbing against hot engine components that could cause insulation breakdown.
3
Disconnect the pump and measure the control circuit voltage — if it remains high with the pump disconnected, the short is in the wiring or ECM. If voltage normalizes, the pump is internally shorted.
4
Check the pump relay by swapping it with an identical relay in the fuse box. Measure relay coil resistance (typically 60-90 ohms) and check for stuck contacts.
5
Measure the resistance of the control wire from the ECM connector pin to the pump connector — should be less than 2 ohms with no shorts to battery voltage. Use a wiring diagram to identify the exact pins.
Estimated Repair Cost
$150 - $650
Parts + labor, varies by vehicle and location
The charge air cooler coolant pump control circuit is reading higher voltage than expected. The ECM has detected that the signal voltage on the pump control wire exceeds the normal operating range. This can prevent the intercooler coolant pump from functioning correctly, resulting in hotter intake a...
The most common cause of P023C (Charge Air Cooler Coolant Pump Control Circuit High) is: Short to voltage in the pump control circuit wiring
Typical repair costs for P023C range from $150 to $650, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Driving is generally safe at moderate speeds, but the intercooler cooling system may not operate correctly. Higher intake air temperatures increase the risk of detonation under load. The ECM will likely de-rate boost pressure as a protective measure. Avoid heavy acceleration and towing until the issue is resolved.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P023C to identify the root cause.
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Quick Info
Category
Powertrain
System
Turbocharger / Supercharger System
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
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