Toyota Celica 2005 Repair Manual page 478

ECM Power Source Circuit
CIRCUIT DESCRIPTION
When the ignition switch is turned ON, battery voltage is applied to terminal IGSW of the ECM. The ECM
"MREL" output signal causes current to flow to the coil, closing the contacts of the EFI relay and supplying
power to terminal +B of the ECM.
If the ignition switch is turned OFF, the ECM holds the EFI relay ON for a maximum of 2 seconds to allow
for the initial setting of the throttle valve.
WIRING DIAGRAM
B−R
FL MAIN
Battery
2005 CELICA (RM1131U)
DIAGNOSTICS
Engine Room J/B
EFI Relay
EFI
1
5
2A
7
1
2H
W−B
− ENGINE (1ZZ−FE)
EFI No. 1
3
2
EB
477
4
16
B−R
2F
E2
12 21
L−B
2F E3
17
BR
E4
A
J1
J/C
A
BR
ED
DI−279
DIC72−02
ECM
+B
MREL
E1
A09126