Honda BF40D Mode D'emploi page 435

DTC 140-2: ECT sensor voltage is too high
1) Symptom reproduction test
a. Turn the combination switch OFF. Disconnect the
ECT sensor 2P connector
again.
b. Clear the DTC (P. 5-12).
• Continue the procedure when the DTC does not
clear.
c. Turn the combination switch ON. Measure the ECT
sensor voltage using the HDS (Dr. H or pocket
tester).
Is the measurement within 0.078 - 4.92V?
YES - Temporary failure (Disappears.)
NO - Go to "2) ECT sensor signal line open-circuit
inspection."
2) ECT sensor signal line open-circuit inspection
a. Turn the combination switch OFF and disconnect
the ECT sensor 2P connector
b. Turn the combination switch ON. Measure the
voltage between the ECT sensor 2P connector
main wire harness side No.1 (Red/Black) terminal
and the engine ground.
ECT SENSOR 2P CONNECTOR
MAIN WIRE HARNESS SIDE
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VIEWED FROM THE TERMINAL SIDE
Is the measurement within 4.30 - 5.25V?
YES - Go to "3) ECT sensor GND line open-circuit
inspection."
NO - Repair open in the main wire harness
between the ECM and the ECT sensor.
3) ECT sensor GND line open-circuit inspection
once and connect it
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.
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4) ECT sensor inspection
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TOH (Red/Black)
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• Turn the combination switch OFF. Check for
continuity between the ECT sensor 2P connector
main wire harness side No.2 (Green/Red)
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terminal and the engine ground.
ECT SENSOR 2P CONNECTOR
MAIN WIRE HARNESS SIDE
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SG2
(Green/Red)
VIEWED FROM THE TERMINAL SIDE
Is there continuity?
YES - Go to "4) ECT sensor inspection."
NO - Repair open in the main wire harness
between the ECM and the ECT sensor.
a. Remove the ECT sensor and connect the ECT
sensor 2P connector .
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b. Turn the combination switch ON and measure the
sensor temperature using the HDS (Dr. H or pocket
tester).
Does the measurement correspond to the ambient
temperature?
YES - Replace the ECM with a new one and
recheck.
NO - Replace the ECT sensor with a new one and
recheck.
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