P04DC

Symptoms

• Check Engine Light Is On
• The system does not correctly determine the position of the tank cap
• Possible false alarms about an open lid
• Intermittent malfunctions of the lid locking system

Causes

• Faulty fuel cap position sensor
• Damage or displacement of the sensor due to impact
• Oxidation of sensor connector contacts
• Unstable voltage in the sensor circuit
• Mechanical damage to the sensor housing

How to Fix

1. Read error codes and check freeze frame data
2. Inspect the cover position sensor for physical damage
3. Check that the sensor is installed correctly
4. Measure the signal voltage at different positions of the cover with a multimeter
5. Clean the connector and contacts from oxidation
6. Check the wiring for chafing and unstable connections.
7. Replace the sensor if the characteristics are outside the norm
8. Reset the error and check the system operation

Related codes

Error P04DC by Vehicle Brand