HONDA marine BF135A, Shop Manual, Page: 26 / 49

5-23
Is the measurement 4.30 – 5.25V?
YES – Repair open in the sensor ground line.
NO – Repair open in the wire between the ECM
and the ECT sensor 1.
4. ECT sensor 1 check
-1. Turn the ignition switch OFF and connect the Dr. H.
-2. Turn the ignition switch ON and check the engine
coolant temperature with the Dr. H.
Is the engine coolant temperature normal?
YES – Substitute a known-good ECM and recheck.
NO – Replace the ECT sensor 1 and recheck.
• TP Sensor Troubleshooting
DTC 7-1: TP sensor voltage is low
1. Symptom reproduction test
-1. Connect the Dr. H and clear the DTC once. If the
DTC can not be cleared, go on the troubleshooting.
-2. Turn the ignition switch ON.
-3. Measure the TP sensor voltage using the Dr. H.
Is the measurement 0.08 – 4.92V?
YES – Temporary failure (Disappeared)
NO – Perform “2. TP sensor signal line short cir-
cuit check”.
2. TP sensor signal line short circuit check
-1. Turn the ignition switch OFF and disconnect the TP
sensor connector.
-2. Disconnect the ECM connector B.
-3. Check for continuity between the No. 2 (Red/Black)
terminal of the TP sensor harness side 3P connector
and the engine ground.
Is there the continuity?
YES – Repair short in the wire between the TP
sensor and the ECM.
NO – Perform “3. TP sensor check”.
3. TP sensor check
-1. Connect the ECM connector B and the TP sensor 3P
connector.
-2. Turn the ignition switch ON and measure the TP sen-
sor voltage using the Dr. H.
Is the measurement voltage 4.49 – 4.85V at full
open throttle and 0.44 – 0.56V at full close throttle?
YES – Substitute a known-good ECM and recheck.
NO – Replace the TP sensor.
TP SENSOR HARNESS
SIDE 3P CONNECTOR
THL (RED/BLACK)
VIEWED FROM THE
TERMINAL SIDE