Honda BF135A Manual page 206

DTC 141-2: ECT sensor 3 voltage is high
1. Symptom reproduction test
-1. Connect the HDS pocket tester and clear the DTC
once. If the DTC can not be cleared, go on the trou-
bleshooting.
-2. Turn the ignition switch ON.
-3. Measure the ECT sensor 3 voltage using the HDS
pocket tester.
Is the measured 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 and disconnect the 2P
connector 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.
ECT SENSOR 3 HARNESS SIDE
2P CONNECTOR
VIEWED FROM THE
TERMINAL SIDE
Is the measured voltage 4.75 – 5.25V?
YES – Perform "3. ECT sensor 3 ground line open
circuit check".
NO – Repair open in the wire between the ECT
sensor 3 and the ECM.
5-53
TOH2 (RED)
3. ECT sensor 3 ground line open circuit check
-1. Connect the ECM connector B.
-2. Check for continuity between the No. 1 (Green/Red)
terminal of the ECT sensor 3 harness side 2P con-
nector and the body ground.
ECT SENSOR 3 HARNESS SIDE
2P CONNECTOR
SG2
(GREEN/RED) (GREEN/RED)
VIEWED FROM THE
TERMINAL SIDE
Is there the continuity?
YES – Perform "4. ECT sensor 3 check".
NO – Repair open in the wire between the ECT
sensor 3 and the engine ground.
4. ECT sensor 3 check
-1. Turn the ignition switch OFF and connect all the con-
nectors.
-2. Turn the ignition switch ON and measure the ECT sen-
sor 3 temperature using the HDS pocket tester.
Does the measurement agree with the engine
coolant temperature?
YES – When the DTC appears again, substitute a
known-good ECM and recheck.
NO – Replace the ECT sensor 3.
BF135A•BF150A