Suzuki WagonR+ RB310 Service Manual page 2440

DTC P0400 EXHAUST GAS RECIRCULATION FLOW MALFUNCTION
CIRCUIT DESCRIPTION
Ignition
switch
Relay
box
Main fuse
DTC DETECTING CONDITION
D While running at specified vehicle speed after
engine warm-up
D During deceleration (engine speed high with closed
throttle position ON) in which fuel cut is involved,
difference in intake manifold absolute pressure
between when EGR valve is opened at specified
value and when it is closed is larger or smaller than
specified value.
2 driving cycle detection logic, monitoring once/1
driving
Main
relay
EGR valve
D EGR valve or its circuit
D EGR passage
D ECM
ENGINE DIAGNOSIS 6-81
POSSIBLE CAUSE