A18639
B–Y
2
2
2
B–O
B–R
J/B No. 1
W–R
R/B No. 2
BR
+B
ECM
IGN
R/B No. 2
J/C
IF1
7
6
E1
D
E
AM2
2
Battery
I14
Ignition
Switch
W–B
1F
11
4
1I
5
2
2
16
2
3
17
1
2
EA
EF
E7
E5
W–R
W–R
EFI Main-
Relay
B–O
W–B
J10
J9
IF1
7
3E
3E
2
J/B No. 3
1
23
From
EFI Fuse
(See page DI–173)
W–R
W
1
DI–206
–
DIAGNOSTICS
ENGINE (2RZ–FE, 3RZ–FE)
468
Author:
Date:
2003 TOYOTA TACOMA (RM1002U)
ECM Power Source Circuit
CIRCUIT DESCRIPTION
When the ignition switch is turned ON, battery positive voltage is applied to the coil, closing the contacts of
the EFI main relay (Marking: EFI) and supplying power to terminal +B of the ECM.
WIRING DIAGRAM
DIB2L–01
A18845
E1 (–)
+B (+)
I05027
3
1
2
5
1
2
5
3
–
DIAGNOSTICS
ENGINE (2RZ–FE, 3RZ–FE)
DI–207
469
Author:
Date:
2003 TOYOTA TACOMA (RM1002U)
INSPECTION PROCEDURE
1
Check voltage between terminals +B and E1 of ECM connectors.
PREPARATION:
(a)
Remove the glove compartment (See page SF–55).
(b)
Turn the ignition switch ON.
CHECK:
Measure the voltage between terminals +B and E1 of the ECM
connectors.
OK:
Voltage: 9 – 14 V
OK
Proceed to next circuit inspection shown on
Problem symptoms table (See page DI–24).
NG
2
Check for open in harness and connector between terminal E1 of ECM and body
ground (See page IN–28).
NG
Repair or replace harness or connector.
OK
3
Check EFI main relay (Marking: EFI).
PREPARATION:
Remove the EFI main relay from RB No. 2.
CHECK:
Inspect the EFI main relay.
OK:
Condition
Tester connection
Specified condition
C
t
t
1 – 2
Continuity
onsan
3 – 5
No continuity
Apply B+ between
terminals 1 and 2.
3 – 5
Continuity
NG
Replace EFI main relay.
OK
A18405
IGN Fuse
J/B No. 1
DI–208
–
DIAGNOSTICS
ENGINE (2RZ–FE, 3RZ–FE)
470
Author:
Date:
2003 TOYOTA TACOMA (RM1002U)
4
Check EFI fuse (See page DI–173, step 2).
NG
Check for short in all harness and components
connected to EFI fuse.
OK
5
Check for open in harness and connector between EFI main relay (Marking: EFI)
and battery, and EFI main relay and ECM (See page IN–28).
NG
Repair or replace harness or connector.
OK
6
Check