TOHATSU BFT75A Service Manual page 127

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TROUBLESHOOTING
MIL AND WARNING BUZZER DOES
NOT OPERATE
1. Fuse inspection
Turn the combination switch OFF.
Check for blown No.2, No.6, and No.5 fuses.
Is the fuse blown?
YES
NO
2. ECM power line inspection
Turn the combination switch OFF.
Disconnect ECM connector B
Turn the combination switch ON.
Measure the battery voltage between the respective
terminals of the main wire harness side No.8
(Yellow/Black) terminal and No.9 (Yellow/Black)
terminal of ECM connector B
ground.
Does battery voltage exist?
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, No.35 (Green) terminal and engine
ground.
Check for continuity between the ECM connector B
No.17 (Green) terminal, No.23 (Blue) terminal,
No.35 (Green) terminal and engine ground.
Is there continuity?
YES
NO
4-14
– Replace the blown fuse and check for
short in the main wire harness or incorrect
load by referring to the "FUSE LOAD
CHART."(page 4-13)
– GO TO STEP 2.
– GO TO STEP 3.
– GO TO STEP 4.
main wire harness side No.17 (Green)
main wire harness side No.5 (Blue) terminal,
– Replace the ECM with a new one and
recheck.
– Repair open in the wire harness between
the ECM and engine ground.
ECM CONNECTOR B
.
MAIN WIRE HARNESS SIDE
and the engine
PG3
.
(Green)
PG1
(Green)
PG2
(Green)
IGP2
(Yellow/Black)
IGP1
(Yellow/Black)
ECM CONNECTOR A
MAIN WIRE HARNESS SIDE
PG4
(Green)
ECM CONNECTOR B
MAIN WIRE HARNESS SIDE
LG2
(Blue)
LG1
(Blue)