Technical Description of OBD-II Trouble Code
The control circuit for the charge air cooler coolant pump is operating at a high level.
What does that mean?
This generic powertrain diagnostic trouble code (DTC) is applicable to all OBD-II vehicles equipped with a charge air cooler, including vehicles from Ford, Chevy, Mazda, Toyota, etc.
In forced induction systems, a charge air cooler or intercooler (IC) is used to cool the air that the engine uses. This works similarly to a radiator.
In the case of the intercooler, it cools the air to create a more efficient air/fuel mixture, resulting in better fuel mileage and performance. In some systems, the intercooler uses a combination of air and coolant to aid in cooling the charge air being forced into the cylinders via forced induction (supercharger or turbocharger).
In these cases, a coolant pump is used to accommodate the additional coolant flow needs. These are typically electronic fluid pumps that supply the necessary coolant flow to the intercooler that the water pump cannot supply independently.
The malfunction indicator lamp (MIL) will illuminate the instrument cluster with the code P023C and associated codes when it detects a condition outside of the specific range within the intercooler’s coolant pump control circuit. Two possible causes are an obstruction within the pump’s openings that causes an electrical value to go out of range, or a chafed control wire that has worn through the electrical connection, resulting in an open circuit. Both mechanical and electrical faults are equally possible.
Code P023C Charge Air Cooler Coolant Pump Control Circuit High is active when there is a high electrical value within the charge air cooler coolant pump and/or its circuit.
What is the severity of this DTC?
The severity of this DTC is low. In most cases, this fault will not pose any immediate safety concerns. However, the drivability and performance of the vehicle may be affected, especially if left unattended for an extended period of time.
What are some of the symptoms of the code?
Symptoms of a P023C engine code may include:
What are some of the common causes of the code?
Causes for this code may include:
What are some P023C troubleshooting steps?
Check for technical service bulletins (TSBs) for your vehicle to access known fixes that can save time and money during diagnosis.
Basic Step #1
First, locate the intercooler (IC) or charge air cooler. Generally, it is located in a position that allows for optimal air flow, such as the front of the radiator, inside the front bumper, or under the hood. Once located, trace the coolant lines/pipes back to the coolant pump. Keep in mind that the pump may be difficult to find as it is typically mounted inline with the coolant flow. Thoroughly inspect the harness around the area for signs of melting or damage.
NOTE: Allow the engine to cool before testing or repairing the cooling system.
Basic Step #2
Verify the integrity of the cooling system by checking the coolant levels and the condition of the coolant. Ensure that it is clean and full before proceeding.
NOTE: Refer to your service manual to determine the specific antifreeze used for your particular make and model.
Basic Tip #3
Measure and record the integrity of the charge air cooler control circuit. Use a multimeter and the appropriate wiring harness to independently test the control circuit. This may involve disconnecting the connector at the engine control module (ECM) and the other end at the coolant pump. Refer to the wiring diagram for specific wiring colors and test procedures.
NOTE: Disconnect the battery before performing any electrical repairs.
Basic Step #4
Depending on the specific system, you may be able to independently test the coolant pump. Remove the coolant pump from the vehicle (which may require draining the system) and power it up using a 12-volt source and a good ground to see if it operates. Also, ensure that it can transfer fluid effectively (note that these pumps are not designed for high pressure or flow, so focus on general operation).
Basic Step #5
Diagnosing the engine control module (ECM) should be a last resort and should only be done if all other diagnostic strategies have been exhausted. This usually involves performing a pinout test at the ECM and comparing the recordings to the desired values.
