Code P023A indicates an open circuit in the control system of the charge air cooler coolant pump (Charge Air Cooler or Intercooler). This system is used in forced induction engines (turbocharged or supercharged) to cool the compressed air before it enters the cylinders, thereby improving combustion efficiency.
System Operation
- Charge Air Cooler (Intercooler): Cools the compressed air via an air/liquid or air/air heat exchanger.
- Dedicated Coolant Pump: An additional electric pump ensures coolant flow to the intercooler, independent of the main water pump.
Code Severity
- Risk Level: Low (no immediate danger), but may lead to:
- Decreased engine performance.
- Localized overheating.
- Increased fuel consumption.
Common Symptoms
- Malfunction Indicator Lamp (MIL) illuminated.
- Loss of power during acceleration.
- Abnormal temperatures (especially under high engine load).
- Risk of pre-detonation (knocking) due to uncooled charge air.
Possible Causes
| Category | Details |
|---|---|
| Electrical Issues | – Open circuit in the pump wiring. – Corroded/disconnected connector. – ECM (Engine Control Module) failure. |
| Mechanical Failures | – Seized coolant pump (debris, corrosion). – Obstruction in coolant lines. |
| Diagnostic Errors | – Insufficient or degraded coolant. – Air bubbles in the system. |
Diagnostic Steps
1. Preliminary Check
- Check TSBs (Technical Service Bulletins): Look for known recalls or software solutions for your model (e.g., Ford EcoBoost, Mazda Skyactiv).
- Inspect coolant: Level, quality (no contamination), and purge any air bubbles.
2. Locate the Coolant Pump
- Typical location: Near the intercooler, often behind the grille or under the hood.
- Identify lines: Follow the coolant hoses from the intercooler.
3. Electrical Test (Multimeter)
- Disconnect the pump and check:
- Resistance: Compare with manufacturer specifications (typically 5-20 Ω).
- Continuity: Between the pump and ECM (look for open or short circuits).
- Inspect the harness: Cracks, burns, or corrosion on connectors.
4. Mechanical Pump Test
- Direct power: Use an external 12V power source to check if the pump operates.
- Flow: If the pump runs but no flow, suspect internal obstruction.
5. ECM Diagnosis
- Advanced OBD2 scanner: Check live data (pump control signal).
- Pin test: Measure ECM output voltage to the pump (should be ~12V upon activation).
Common Repairs
| Problem | Solution | Estimated Cost |
|---|---|---|
| Faulty pump | Replace the pump. | 150-400 € (part + labor) |
| Open circuit | Repair wiring or replace connector. | 50-150 € |
| Poor connection | Clean terminals or replace connector. | 20-80 € |
Post-Repair Best Practices
- Reset the code with an OBD2 scanner.
- Road test: Verify the pump activates under load (using a live diagnostic tool).
- Monitoring: Check temperatures and performance over several driving cycles.
Do Not Ignore
If code P023A reappears after repair, check:
- Coolant compatibility (some models require a specific type).
- ECM software updates (some manufacturers fix bugs via recall).
ℹ️ Pro tip: On high-end vehicles (e.g., Audi, BMW), use a manufacturer-specific diagnostic tool (e.g., VCDS, ISTA) to access specific cooling system parameters.