TOHATSU BFT115A Service Manual page 157

DTC 23-1 (ABNORMAL KNOCK SENSOR DETECTION)
ECM
KS
1. Symptom reproduction test
Turn the combination switch OFF.
Disconnect the knock sensor 1P connector
and ECM connector B
them.
Clear the DTC (page 5-6).
• 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 until the engine
temperature is over 85 °C (185 °F).
Increase the engine speed gradually and run it at
-1
3,000 – 4,000 min (rpm) for 10 seconds.
Recheck the DTC with the HDS.
Does the DTC 23-1 appear?
YES – GO TO STEP 2.
NO – Temporary failure
reappear)
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
40
No.1 (Red/Blue) terminal and ECM connector B
No.29 (Red/Blue) terminal.
13
Is the knock sensor line normal?
YES – Replace the knock sensor with a new one
and recheck. If the knock sensor is
replaced, but DTC 23-1 still appears,
replace the ECM with a new one and
recheck.
NO – Repair open or short in the Red/Blue wire.
R/Bu R/Bu
13
Bu
40
, and then reconnect
13
-1 (rpm) for
(code does not
40
.
13
main wire harness side
KNOCK
SENSOR
40
Bl Black Br Brown
Y Yellow O Orange
Blue Lb Light blue
Lg
G Green Light green
R Red P Pink
W White Gr Gray
FUEL SYSTEM
5-39