Honda BF135A Manual page 217

BF135A•BF150A
• MIL ON but MIL Does Not Blink
With SCS Circuit Shorted
1. Engine start check
-1. Disconnect the SCS short connector and start the
engine.
Does the engine start?
YES – Perform "2. Data link connector line check".
NO – Perform "3. Sensor check".
2. Data link connector line check
-1. Turn the ignition switch OFF and connect the test har-
ness (P. 5-58).
-2. Disconnect the test harness sensor connector.
-3. Turn the ignition switch ON. Measure the voltage
between the test harness B-16 terminal (+) and A-1
terminal (–), and between the B-16 terminal (+) and B-
17 terminal (–).
A-1
Is the measured voltage 4.30 – 5.25V?
YES – Go to the step 4.
NO – Substitute a known-good ECM and recheck.
-4. Turn the ignition switch OFF and connect the test har-
ness.
-5. Turn the ignition switch ON. Measure the voltage
between the test harness B-16 terminal (+) and A-1
terminal (–), and between the B-16 terminal (+) and B-
17 terminal (–).
A-1
Is the measured voltage 4.30 – 5.25V?
YES – Repair open in the wire harness between the
ECM and the data link connector.
NO – Go to the step 6.
-6. Connect the SCS short connector to the data link con-
-7. Measure the voltage between the test harness B-16
-8. Disconnect the SCS short connector.
-9. Turn the ignition switch OFF. Check for the continuity
B-16
B-17
B-16
-10. Disconnect the SCS short connector from the data link
-11. Turn the ignition switch OFF and disconnect the ECM
B-17
-12. Turn the ignition switch ON and check that the MIL
nector to short-circuit.
terminal (+) and A-1 (–) terminal, and between the B-
16 terminal (+) and B-17 terminal (–).
A-1
Is the measured voltage 4.30 – 5.25V?
YES – Go to the step 8.
NO – Go to the step 10.
between the data link connector No. 1 (Black) terminal
and the engine ground.
DATA LINK CONNECTOR
VIEWED FROM THE TERMINAL SIDE
Is there the continuity?
YES – Repair open in the main harness between the
data link connector and the ECM.
NO – Repair open in the main harness between the
data link connector and the engine ground.
connector.
connector A.
comes ON.
Does the MIL come ON?
YES – Repair short in the main harness (Red/Blue)
between the MIL and the ECM.
NO – Substitute a known-good ECM and recheck.
B-16
B-17
5-64