P023E - Charge Air Cooler Coolant Temperature Sensor / Intake Air Temperature Sensor Correlation
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System
Powertrain (Engine & Gearbox)
Related Fault Codes
Technical Description
P023E is a correlation fault between the Charge Air Cooler (CAC) temperature sensor and the Intake Air Temperature (IAT) sensor. The Engine Control Unit (ECU) monitors the thermal efficiency of the intercooler system. If the temperature differential between the ambient air/intake air and the pressurized charge air is outside of the mapped calibrated range, the ECU determines that the cooling efficiency is compromised. This is particularly prevalent in liquid-to-air intercooler systems where a dedicated electric pump and coolant circuit are used.
Possible Causes
Defective or clogged charge air cooler coolant pump (electric pump)
Low coolant level in the secondary cooling circuit
Faulty temperature sensor (IAT 2 / Charge Air Temp sensor)
Internal restriction or blockage within the charge air cooler core
Symptoms
Recommended Solution
- Visual Inspection: Check the coolant level in the dedicated charge air cooler reservoir. Inspect the auxiliary radiator for damage or debris.
- Measurement (Pump): Activate the electric coolant pump using a bi-directional scan tool. Verify 12V supply and ground. Normal current draw is typically 2-5 Amps.
- Measurement (Sensors): Test temperature sensors with a multimeter. At 68°F (20°C), expected resistance is usually 2000-3000 Ohms (check OEM specs). Compare sensor readings in Live Data; on a cold engine, all IAT/Coolant sensors should match ambient temperature.
- Component Replacement: Bleed the cooling system thoroughly after pump or sensor replacement using a vacuum filler if required by the manufacturer.
Mechanic's Tip
Before replacing expensive components, always double-check wiring and connections. 80% of all sensor faults are actually due to corroded contacts or broken wires.
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