The P0400 trouble code is associated with Exhaust Gas Recirculation (EGR) Flow Malfunction, indicating an issue with the flow of exhaust gases being recirculated into the engine.
Exhaust Gas Recirculation Flow Malfunction
Code symptoms P0400.
1. Illuminated “Check Engine” or “Service Engine Soon” light on the dashboard.
2. Poor engine performance.
3. Increased emissions.
This code is common in brands such as:: Chevrolet, Renault, Ford, Toyota, Nissan, Mercedes Benz, Honda.
Causes of the code P0400.
1. EGR valve stuck open or closed.
2. Faulty EGR position sensor.
3. Clogged EGR passages.
4. Wiring or connection issues in the EGR system.
5. Problems with the Engine Control Module (ECM).
Code Solutions P0400.
1. Inspect and, if necessary, replace the EGR valve.
2. Check and replace the EGR position sensor if it’s faulty.
3. Clean or replace clogged EGR passages.
4. Inspect and repair any faults in the wiring or connections of the EGR system.
5. If ECM issues are suspected, consult a qualified technician for diagnosis and potential reprogramming or replacement.