Downloaded from www.Manualslib.com manuals search engine FI4825
EGR
Vacuum
Modulator ECM
VSV EGR Valve Throttle Body
Throttle
Valve
Intake Air
Chamber
Exhaust Gas
P19921
R/B No.2 IG Switch
E4 E5
(M/T)(A/T)
E01
E1 ECM
E2 EGR
THG
E6 E6
E6 E6
18 8
21 14
922 1
BR−B P2
2
1 9 9
EA
W−R W−R
IE1W−REA1
W−B
2 3
2
2 2
2 2
2
2
1 1
5 B−W
EFIEFI Relay
VSV for EGR
EGR Gas
Temp. SensorB−YEA14B−Y
1C17
1A3
W−R IGNJ/B
No.1FromFrom Battery
R−W
5 V DI−196
− DIAGNOSTICSENGINE (5VZ−FE)
1996 TOYOTA T100 (RM449U)
DTC P0401 Exhaust Gas Recirculation Flow Insufficient
Detected*
*: Only for 2WD models with a load capacity of 0.5 ton and regular cab.
CIRCUIT DESCRIPTION
The EGR system recirculates exhaust gas which is controlled to the proper quantity to suit the driving condi-
tions, into the intake air mixture to slow down combustion, reduce the combustion temp. and reduce NOx
emissions. The amount of EGR is regulated by the EGR vacuum modulator according to the engine load.
If even one of the following conditions is fulfilled, the VSV is
turned ON by a signal from the ECM.
This results in atmospheric air acting on the EGR valve, closing
the EGR valve and shutting off the exhaust gas (EGR cut−off).
Under the following conditions, EGR is cut to maintain
driveability:
Before the engine is warmed up
During deceleration (throttle valve closed)
Light engine load (amount of intake air very small)
Engine racing
DTC No.DTC Detecting ConditionTrouble Area
P0401
After engine is warmed up and run at 80 km/h (50 mph)
for 3 to 5 min., EGR gas temp. sensor valve does not
exceed 60°C (140°F) above ambient air temp.
(2 trip detection logic)EGR valve stuck closed
Short in VSV circuit for EGR
Open in EGR gas temp. sensor circuit
EGR hose disconnected
ECM
WIRING DIAGRAM
DI0UX−01
