Exhaust Gas Recirculation Flow Malfunction

FAULT ID
P0400

TITLE
Exhaust Gas Recirculation Flow Malfunction

BACKGROUND
- When the Exhaust Gas Recirculation (EGR) solenoid switches from OFF to ON while the engine is running, EGR gas flows.
- The engine control module checks how the EGR gas flow signal changes.

RANGE OF CHECK & SET CONDITIONS
The EGR gas flow signal changes little when the EGR solenoid switches from OFF to ON.

EFFECT
Limp-in

PROBABLE CAUSES
- EGR valve does not open.
- EGR control vacuum is too low.
- EGR solenoid failed.
- Open or shorted EGR solenoid circuit, or loose connector.
- Manifold differential pressure sensor failed.
- Engine control module failed.