4-68 FI SYSTEM DIAGNOSIS
Step 3
FP relay drive circuit check
1) Turn the ignition switch OFF.
2) Disconnect the ECM couplers
1
.
3) Check for proper terminal connection to the ECM couplers.
4) If connections are OK, check the following points.
• Resistance
09900-25008: Multi circuit tester set
09900-25009: Needle-point probe set
Tester knob indication: Resistance (
)
– Between O/Bl wire and Y wire of FP relay coupler and ECM
coupler: less than 1
– Between O/Bl or Y wire and ground: infinity
• Voltage
09900-25008: Multi circuit tester set
Tester knob indication: Voltage (
)
– Between O/Bl wire or Y wire and ground: approx. 0 V
(When ignition switch is ON)
Is check result OK?
3
3
3
YES
Replace the ECM with a known good one, and
inspect it again.
NO
Repair or replace the defective wire harness.
3
