Exhaust gas recirculation (EGR)

Exhaust Gas Recirculation (EGR)

The Exhaust Gas Recirculation (EGR) system redirects a small portion of exhaust gases from the exhaust manifold back into the intake manifold (see the diagram) to lower the combustion temperature. The engine computer regulates the flow of the EGR gases by opening or closing the EGR valve. The EGR flow is at its maximum during steady highway cruising. The engine computer periodically tests the operation of the EGR system. If the engine computer detects that the EGR flow is less or greater than expected, it sets the fault code P0400 - Exhaust Gas Recirculation Flow Malfunction.

Removing exhaust gas recirculation valve

19 - Intake manifold 89 - Exhaust gas recirculation valve 89/1 - Exhaust gas recirculation line 89/2 - Vacuum reservoir 89/3 - Union nut a - Vacuum line from intake pipe b - Vacuum line Y31/1 - ARF vacuum transducer

1 - Oil dipstick guide tube 2 - Fuel rail 3 - Plug connection 89 - Exhaust gas recirculation valve 89/3 - Union nut Y31/1 - ARF vacuum transducer

1. Remove cover on front side of engine
2. Remove air filter housing
3. Remove engine cover with integrated air filter
4. Unplug connector on EGR pressure transducer (Y31/1).
5. Detach vacuum line (b) to vacuum unit (89/2) and EGR pressure transducer (Y31/1)
6. Unscrew union nut (89/3) on exhaust gas recirculation valve (89)
7. Dismount EGR line (89/1) from intake manifold (19)
8. Unscrew exhaust gas recirculation pipe (89) from cylinder head
9. Remove exhaust gas recirculation valve (89). Installation: Replace gaskets. Note length and routing of vacuum line from intake manifold to EGR [ARF] vacuum transducer (Y31/1). Incorrect routing may cause throttle lever to jam.
10. Install in the reverse order

Fault codes

P0400 Exhaust Gas Recirculation Flow Malfunction