P06AC

Symptoms

• Check Engine Light Is On
• Unreliable ECU temperature readings according to scanner data
• Possible emergency mode due to incorrect thermal information
• Unstable performance at temperature extremes
• Random engine control errors

Causes

• Degradation of internal temperature sensor B on the ECU board
• Exposure to moisture that changes sensor performance
• Previous overheating that damaged the sensor
• Deviation of sensor characteristics due to aging
• Soldering defect or microcrack in the sensor circuit

How to Fix

1. Read error codes and analyze ECU temperature readings on a scanner
2. Compare sensor B readings with actual operating conditions
3. Check code history for P06AA (overheating) as the root cause
4. Inspect the ECU for traces of moisture and corrosion on the connectors
5. Send the ECU for diagnostics to a specialized workshop
6. If repair is impossible, replace the ECU

Related codes

Error P06AC by Vehicle Brand