P0402 Fault Code
P0402 OBD-II Trouble Code Short Description
Exhaust Gas Recirculation Flow Excessive Detected
What does trouble code P0402 mean?
The P0402 fault code indicates that the Engine Control Module (ECM) has detected excessive flow in the Exhaust Gas Recirculation (EGR) system. This can lead to poor engine performance and increased emissions. The EGR system is designed to help reduce nitrogen oxide (NOx) emissions by recirculating a portion of the exhaust back into the engine intake. When the flow is excessive, it may suggest a malfunctioning EGR valve or other related components.
Symptoms
What are the symptoms of the P0402 code?
- Check Engine Light illuminated
- Rough idling or stalling
- Decreased engine performance
- Increased emissions
- Poor fuel economy
Causes
What causes the P0402 code?
- Stuck open EGR valve
- Faulty EGR position sensor
- Blocked EGR passages
- Vacuum leaks in the EGR system
- Improperly installed or damaged gaskets
Possible Solutions
How to fix P0402?
- Inspect the EGR valve for proper operation and free movement
- Replace the EGR valve if it is stuck open
- Clean any blockages in the EGR passages
- Check and replace faulty sensors associated with the EGR system
- Ensure all connections are secure and vacuum leaks are repaired