Explanation:
The exhaust gas recirculation (EGR) system reduces nitrogen oxide (NOx) emissions by recirculating a portion of the exhaust gas back into the engine. The powertrain control module (PCM) controls the EGR valve to regulate the amount of exhaust gas recirculated. The PCM monitors the EGR system flow to ensure that it is within the desired range. If the PCM detects that the EGR system flow is excessive, it will set the P1401 code.
Possible Causes:
- Faulty EGR valve
- EGR valve stuck open
- Damaged EGR vacuum hose
- Leaking EGR gasket
- Faulty PCM
Solutions:
- Replace the EGR valve.
- Clean the EGR valve and make sure it is not stuck open.
- Inspect the EGR vacuum hose for damage and replace if necessary.
- Replace the EGR gasket if it is leaking.
- Have the PCM diagnosed and repaired or replaced if necessary.
