TOHATSU BFT75A Service Manual page 179

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FUEL SYSTEM
2. Knock sensor line open or short circuit
inspection
Turn the combination switch OFF.
Disconnect the knock sensor 1P connector
and ECM connector B
Check for open and short circuit between the knock
sensor 1P connector
No.1 (Red/Blue) terminal and ECM connector B
Is the knock sensor line normal?
YES
NO
3. Knock sensor inspection
Replace the knock sensor with a new one (page 5-
84).
Perform the knock sensor symptom reproduction
test (page 5-37).
Does the DTC 23-1 appear?
YES
NO
DTC 41-2 (HO2S HEATER FAILURE)
Bl BLACK Br BROWN
Y YELLOW O ORANGE
Bu BLUE Lb LIGHT BLUE
G GREEN Lg LIGHT GREEN
R RED P PINK
W WHITE Gr GRAY
1. Symptom reproduction test
Turn the combination switch OFF.
Disconnect the HO2S 4P connector
ECM connector A
Clear the DTC (page 5-5).
• Continue the procedure if the DTC does not
clear.
Start the engine and let it run at 3,000 min
5 minutes or more under no load.
Check the DTC using the Dr.H
Does the DTC 41-2 appear?
YES
5-38
.
main wire harness side
No.29 (Red/Blue) terminal.
– GO TO STEP 3.
– Repair open or short in the Red/Blue wire.
– Replace the ECM with a new one and
recheck.
– Faulty original knock sensor.
No.4
FUSE
(10 A)
13
ECM
JOINT
29
CONNECTOR 1
O2HT W/Bl
, and joint connector 1
,and then reconnect them.
– GO TO STEP 2.
Y
16
17
25
W/Bl
Y/Bl
, and
-1 (rpm) for
HO2S
HEATER
W
W