Toyota Celica 2005 Repair Manual page 862

MIL Circuit
CIRCUIT DESCRIPTION
The ignition switch provides circuit power and the ECM provides the circuit ground that illuminates the MIL.
MIL operation is checked visually:
It should be illuminated when the ignition is first turned on. If the MIL is off all of the time or on all of the time,
use the procedure below to troubleshoot it. The MIL is used to indicate the ECM's detection of vehicle mal-
function. Follow this procedure using the hand−held tester or an OBD II scan tool to determine the cause
of the problem and to check the MIL.
WIRING DIAGRAM
R−Y
I10
Ignition Switch
AM1 IG1
1
W
FL MAIN
Battery
INSPECTION PROCEDURE
HINT:
Troubleshoot each trouble symptom in accordance with the chart below.
MIL remains on
MIL is not illuminated
2005 CELICA (RM1131U)
DIAGNOSTICS
Combination Meter
(Malfunction Indicator Lamp)
22
C12
Instrument Panel J/B
WARNING IG1 Relay
11
IM
6
8
L−R
IK
2
AM1
5
IK
Engine Room J/B
ALT
1
B−R
2A
1
− ENGINE (2ZZ−GE)
7
R−B
C13
5
A 3
12
II
1
2
1
IA
1
2E
2
Start inspection from step 1
Start inspection from step 3
861
11
12
R−B
E9
IE5
W
W−B
B−R
IF
DI−663
DIC81−02
ECM
A21373