05–308

DIAGNOSTICS – SFI SYSTEM (2ZZ–GE) 057IF–03

ECM POWER SOURCE CIRCUIT

CIRCUIT DESCRIPTION
When the ignition switch is turned ON, battery positive voltage is applied to the coil which closes the contacts
of the E.F.I. relay (Marking: E.F.I.) and supplies power to the terminal +B of the ECM.
WIRING DIAGRAM

Ignition Instrument ECM

Switch Panel J/B
5 6 9
5 6 B–W B–O
IL IL E6 IGSW
AM2 IG2
B

6 IM
8
B–W E6 MREL
AM2 Instrument
Panel J/B
IG2 7
3 IM
B–W
B–R
EA1 3
IA5 2
R–W B–W
B–R

1 1 1 1

2 2 5 1
EFI Engine Room
MAIN EFI
Relay R/B and J/B
1 1 3 2

1 1A 1 1

B B

FL EA1 9 W–B
MAIN 6 1 3 1
B B B
IG1 4B 4B E6 +B

Center J/B

Battery
EB

A66756

2003 COROLLA MATRIX (RM940U)

Author: Date: 508

 05–309
DIAGNOSTICS – SFI SYSTEM (2ZZ–GE)

INSPECTION PROCEDURE
1 INSPECT ECM

(a) Turn the ignition switch ON.

E1 +B (b) Measure voltage between the terminals +B of the ECM
connector and E1 of the ECM connector.
Voltage: 9 – 14 V

OK CHECK AND REPLACE ECM

A65741

NG

2 CHECK HARNESS AND CONNECTOR(ECM GROUND)

(a) Disconnect the battery negative (–) terminal.

(b) Disconnect the ECM E3 and E4 connector.
(c) Check continuity between the terminal E1 of the ECM
connector and body ground.
Resistance: 1 Ω or less
(d) Check continuity between the terminal E2 of the ECM
connector and body ground.
E2 E1 Resistance: 1 Ω or less
A65746
NG REPAIR OR REPLACE HARNESS AND
CONNECTOR

OK

3 CHECK RELAY(E.F.I. RELAY)

(a) Remove the E.F.I. relay.

(b) Check continuity between the terminals shown below.
Resistance:
TERMINAL NO. RESISTANCE
1–2 1 Ω or less
3–5 1 ΜΩ or more
(c) Check continuity between the terminals 3 and 5 of the
connector when the battery voltage is applied to the termi-
E34090 nals between 1 and 2.
Resistance:
TERMINAL NO. RESISTANCE
3–5 1 Ω or less

NG REPLACE RELAY

OK

2003 COROLLA MATRIX (RM940U)

Author: Date: 509

05–310
DIAGNOSTICS – SFI SYSTEM (2ZZ–GE)

4 CHECK FUSE(E.F.I. FUSE)

(a) Remove the E.F.I. fuse.

(b) Check continuity of E.F.I. fuse.
Resistance: 1 Ω or less

E.F.I.
A65754 NG REPLACE FUSE

OK

5 CHECK RELAY OPERATION(E.F.I. RELAY)

(a) Remove the E.F.I. relay.

(b) Confirm that the E.F.I. relay operates normally when turn-
ing the ignition switch ON.
Result:
E.F.I. relay operation sound is heard successively
when turning the ignition switch ON.

A65750
NG Go to step 9

OK

2003 COROLLA MATRIX (RM940U)

Author: Date: 510

 05–311
DIAGNOSTICS – SFI SYSTEM (2ZZ–GE)

6 CHECK HARNESS AND CONNECTOR(ECM–E.F.I.RELAY)

(a) Disconnect the battery negative (–) terminal.

(b) Remove the E.F.I. relay.
(c) Check continuity between the terminals 1 of the E.F.I.
relay in the engine room R/B and +B of the ECM connec-
tor.
Resistance: 1 Ω or less
(d) Check short between the terminals 1 of the E.F.I. relay in
the engine room R/B and E2 of the ECM.
A65750 Resistance: 1 MΩ or more

+B

E2 NG REPAIR OR REPLACE HARNESS AND

A65741 CONNECTOR

OK

7 CHECK HARNESS AND CONNECTOR(E.F.I. FUSE–BATTERY)

(a) Disconnect the battery negative (–) connector.

(b) Remove the E.F.I. fuse.
(c) Check continuity between the terminals 1 of the E.F.I.
fuse holder in the engine room R/B and negative (–) of the
battery.
NOTICE:
2 Do not insert the tester leads hard in the procedure (c), or
1 the holder may be damaged.
A65756
NG REPAIR OR REPLACE HARNESS AND
CONNECTOR

OK

REPLACE ECM

2003 COROLLA MATRIX (RM940U)

Author: Date: 511

05–312
DIAGNOSTICS – SFI SYSTEM (2ZZ–GE)

8 INSPECT IGNITION OR STARTER SWITCH ASSY

(a) Check continuity between the connector terminals shown

in the chart below.
Switch Terminal No. Resisitance
LOCK All Terminals 1MΩ or more
ACC 1–3 1Ω or less
1–2–3
ON 1Ω or less
5–6
4–5–6
START 1Ω or less
1–2
B50489

NG REPLACE IGNITION OR STARTER SWITCH

ASSY

OK

9 CHECK HARNESS AND CONNECTOR(IGNITION SWITCH–E.F.I. CIRCUIT

OPENING RELAY)

(a) Disconnect the battery negative (–) terminal.

(b) Remove the E.F.I. circuit opening relay.
(c) Disconnect the ignition switch connector.
(d) Check continuity between the terminals IG2 of the ignition
switch connector and 5 of the E.F.I. circuit opening relay
in the R/B.
Resistance: 1 Ω or less
(e) Check for short between the terminal IG2 of the ignition
IG2
A65764 switch and body ground.
Resistance: 1 MΩ or more
Instrument Panel J/B

NG REPAIR OR REPLACE HARNESS AND

A65765
CONNECTOR

OK

REPLACE ECM

2003 COROLLA MATRIX (RM940U)

Author: Date: 512