Honda BF135A - Ect Sensor 3 Troubleshooting

5-86
• ECT Sensor 3 Troubleshooting
MIL blinks 25 times
1. Symptom reproduction test
-1. Reset the ECM.
-2. Turn the ignition switch OFF and connect the test har-
ness.
• Hold the sensor connector connected.
-3. Turn the ignition switch ON.
-4. Measure the voltage between the test harness A-16
terminal (+) and the A-2 terminal (–).
Is the voltage 0.08 – 4.99V?
YES – Temporary failure (Disappeared)
NO – Perform "2. ECT sensor 3 signal line open cir-
cuit check".
2. ECT sensor 3 signal line open circuit check
-1. Turn the ignition switch OFF. Disconnect the 2P con-
nector from the ECT sensor 3.
-2. Turn the ignition switch ON.
-3. Measure the voltage between the No. 2 (Red) terminal
of the ECT sensor 3 harness side 2P connector and
the engine ground.
Is the voltage 4.75 – 5.25V?
YES – Perform "3. ECT sensor 3 signal line short cir-
cuit check".
NO – Repair open in the wire between the ECT
sensor 3 and the ECM.
3. ECT sensor 3 signal line short circuit check
-1. Turn the ignition switch OFF. Disconnect the ECT sen-
sor 3 connector and the ECM connector B.
-2. Check for the continuity between the No. 2 (Red) ter-
minal of the ECT sensor 3 harness side 2P connector
and the body ground.
Is there the continuity?
YES – Repair short in the wire between the ECT
sensor 3 and the engine ground.
NO – Perform "4. ECT sensor 3 ground line open
circuit check".
4. ECT sensor 3 ground line open circuit check
-1. Connect the ECM connector B.
-2. Check for the continuity between the No. 1 (Green/
Red) terminal of the ECT sensor 3 harness side 2P
connector and the body ground.
Is there the continuity?
YES – Perform "5. ECT sensor 3 check".
NO – Repair open in the wire between the ECT
sensor 3 and the engine ground.
BF135A•BF150A
ECT SENSOR 3 HARNESS SIDE
2P CONNECTOR
VIEWED FROM THE TERMINAL SIDE
TOH2 (RED)
ECT SENSOR 3 HARNESS SIDE
2P CONNECTOR
VIEWED FROM THE TERMINAL SIDE
TOH2 (RED)
ECT SENSOR 3 HARNESS SIDE
2P CONNECTOR
VIEWED FROM THE TERMINAL SIDE
SG2 (GREEN/RED)
A-2
A-16