Open circuit in the pump control wire, such as a broken wire or disconnected connector; Short to voltage on the control circuit, often from chafed wiring near hot or moving components; Failed charge air cooler coolant pump with an open internal winding or faulty control module; Corroded or damaged pump electrical connector causing high resistance; Faulty powertrain control module driver for the pump circuit, though this is less common; Aftermarket or incorrect pump installed that does not match the expected control signal; Poor ground connection for the pump, which can skew the control circuit voltage

DTC codes / P02xx · Fuel and air metering (injector circuits) / P023C

P023CCharge Air Cooler Coolant Pump A Control Circuit High

Q: What does code P023C mean?

Charge Air Cooler Coolant Pump A Control Circuit High. P023C indicates that the powertrain control module has detected an abnormally high voltage on the control circuit for the charge air cooler coolant pump, which is the electric pump that circulates coolant through the air-to-liquid intercooler. The high voltage reading tells the module that the circuit is likely open, shorted to voltage, or that the pump's internal electronics are not drawing the expected current.

P023C indicates that the powertrain control module has detected an abnormally high voltage on the control circuit for the charge air cooler coolant pump, which is the electric pump that circulates coolant through the air-to-liquid intercooler. The high voltage reading tells the module that the circuit is likely open, shorted to voltage, or that the pump's internal electronics are not drawing the expected current.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering (injector circuits)

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms
Reduced engine power or limp mode during sustained boost or towing
Poor acceleration or sluggish throttle response when the engine is heat-soaked
Elevated intake air temperatures that may trigger additional codes
In rare cases, the coolant pump may run continuously or not at all, affecting intercooler efficiency
A whining or humming noise from the pump area that changes with key-on or engine running

Common causes, most likely first

Open circuit in the pump control wire, such as a broken wire or disconnected connector
Short to voltage on the control circuit, often from chafed wiring near hot or moving components
Failed charge air cooler coolant pump with an open internal winding or faulty control module
Corroded or damaged pump electrical connector causing high resistance
Faulty powertrain control module driver for the pump circuit, though this is less common
Aftermarket or incorrect pump installed that does not match the expected control signal
Poor ground connection for the pump, which can skew the control circuit voltage

How to diagnose and fix it

Verify the code with a scan tool and check for related codes in the powertrain control module
Inspect the pump connector and wiring harness for corrosion, damage, or loose pins
Measure resistance and voltage on the control circuit according to the factory wiring diagram
Test the pump directly with a known-good power and ground source to confirm operation
Check the pump ground circuit for excessive resistance and repair as needed
If the circuit tests good, replace the charge air cooler coolant pump with a quality OEM or equivalent unit
Clear the code and perform a road test to confirm the repair and ensure the monitor runs

What the high voltage reading really means

A high voltage on the control circuit often indicates an open circuit rather than a short, so a broken wire or unplugged connector is a common find.
The charge air cooler coolant pump may only run under certain conditions such as high boost or high ambient temperature, so a static test may not reveal the fault.
Some vehicles use a pulse-width modulated signal to control pump speed, and a failed pump can back-feed voltage that sets this code without any driveability complaint.
A weak or corroded ground for the pump can cause the control circuit to read high, leading to misdiagnosis of the pump itself.
This code can be set by a low coolant level or air lock in the charge air cooler system, which causes the pump to overheat and draw abnormal current.

Can I keep driving with P023C?

You can usually drive the vehicle with this code, but avoid sustained heavy throttle or towing until it is repaired because the intercooler may not cool effectively and the engine can enter limp mode. If the check engine light flashes or you notice severe power loss, stop driving and have the vehicle inspected.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.