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A99075
5
2
6
4
3
1
Y--G
EGR4
ECM
EGR2
E21
EGR Valve Assy
B--W
E24
B--W
B--W
E24
E24
E24 EGR1
EGR3
3
From EFI MAIN Relay
IE2
4
IE2
IE2
IE2
10
11
Y--G
30
11
31
12
G--B
G--B
R--L
R--L
G
G
--
DIAGNOSTICS
ECD SYSTEM (1ND--TV)
05--117
COROLLA Supplement (RM1129E)
DTC
P0400
EXHAUST GAS RECIRCULATION FLOW
CIRCUIT DESCRIPTION
The EGR (Exhaust Gas Recirculation) system recirculates exhaust gases, which are controlled to the proper
volume in accordance with driving conditions. The recirculated gas mingles with the intake air, therefore
slowing down the engine combustion and lowering the combustion temperature. This helps reduce nitrogen
oxide (NOx) emissions.
In order to increase circulatory efficiency, the ECM adjusts the lift of the EGR valve and intake shutter valve
(throttle valve).
DTC No.
DTC Detection Condition
Trouble Areas
P0400
Target and actual mass air flow rates differ
(The MIL is illuminated and a DTC is set when the same mal-
function is detected on 2 consecutive trips*
*: One trip is counted when the ignition switch is turned from
OFF to ON and back to OFF)
S
Open or short in EGR circuit
S
EGR valve assembly
S
EGR passage
S
Intake shutter
S
Mass air flow meter
S
Contamination in mass air flow meter
S
ECM
HINT:
S
DTC P0400 is set while the engine is running in steady condition.
S
If DTC P0403 has already been set, P0400 is not set.
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:
Read freeze frame data using an intelligent tester ll. Freeze frame data record the engine condition when
malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was
moving or stationary, if the engine was warmed up or not, and other data from the time the malfunction oc-
curred.
05MS1--01
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TOYOTA COROLLA REPAIR MANUAL SUPP 1129E