TOHATSU BFT250A Service Manual page 109

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MIL AND WARNING BUZZER DOES
NOT OPERATE
1. Fuse inspection
Turn the combination switch OFF.
Check for blown No.4, No.5, and No.9 fuses.
Is the fuse blown?
YES
NO
2. ECM power line inspection
Install the No.4, No.5 and No.9 fuses in the fuse/
relay junction box.
Disconnect ECM connector B
Turn the combination switch ON.
Measure the voltage between the main wire harness
side No.8 (Yellow/Black) terminal of ECM connector
B
Measure the voltage between the main wire harness
side No.9 (Yellow/Black) terminal of ECM connector
B
Is battery voltage present?
YES
NO
3. ECM ground line inspection
Turn the combination switch OFF.
Disconnect the ECM connector A
Check for continuity between the ECM connector A
terminal and engine ground.
Check for continuity between the ECM connector B
terminal, No.17 (Green) terminal, No.23 (Green/
Black) terminal, No.35 (Green) terminal and engine
ground.
Is there continuity?
YES
NO
– Replace the blown fuse and check for
short in the main wire harness or incorrect
load by referring to the fuse load chart
(page 4-16).
– GO TO STEP 2.
and engine ground.
and engine ground.
– GO TO STEP 3.
– GO TO STEP 4.
main wire harness side No.17 (Green)
main wire harness side No.5 (Green/Black)
– Replace the ECM with a new one and
recheck.
– Repair the open circuit in the wire harness
between the ECM and engine ground.
ECM CONNECTOR B
MAIN WIRE HARNESS SIDE
.
.
PG3
(Green)
PG2
(Green)
TROUBLESHOOTING
IGP 1
(Yellow/
Black)
ECM CONNECTOR A
MAIN WIRE HARNESS SIDE
ECM CONNECTOR B
MAIN WIRE
HARNESS SIDE
PG1
(Green)
IGP 2
(Yellow/
Black)
LG1
(Green/
Black)
LG2
(Green/
Black)
4-17