Engine General Information and Diagnosis: 1A-87
6 Wire harness check
1) Turn OFF ignition switch.
2) Remove ECM from its bracket with ECM connectors
connected.
3) Check for proper connection of ECM connector at “C37-
43” and “C37-54” terminals.
4) If OK, measure voltage between “C37-54” terminal of
ECM connector and engine ground with ignition switch
turned ON.
Is voltage 4 -6 V?
“GRN” wire is open or
high resistance circuit.
Go to Step 7.
7 Wire harness check
1) Disconnect connectors from ECM with ignition switch
turned OFF.
2) Measure resistance between “GRN” and “RED” wire
terminals of electric throttle body connector.
Is resistance infinity?
Go to Step 8. “GRN” wire is shorted to
“RED” wire.
8 Wire harness check
1) Turn ON ignition switch.
2) Measure voltage between “C37-54” terminal of ECM
connector and engine ground.
Is voltage 0 V?
Substitute a known-
good ECM and recheck.
“GRN” wire is shorted to
power circuit.
9 Ground circuit check
1) Turn OFF ignition switch.
2) Measure resistance between “BLK” wire terminal of
electric throttle body connector and engine ground.
Is resistance below 5
Ω
?
Go to Step 11. Go to Step 10.
10 Ground circuit check
1) Remove ECM from its bracket with ECM connectors
connected.
2) Check for proper connection of ECM connector at “C37-
42” terminal.
3) Measure resistance between “C37-42” terminal of ECM
connector and engine ground with ignition switch turned
OFF.
Is resistance below 5
Ω
?
“BLK” wire is open or
high resistance circuit.
Faulty ECM ground
circuit. If circuit is OK,
substitute a known-
good ECM and recheck.
11 Electric throttle body check
1) Check TP sensor referring to “Throttle Position Sensor
Performance Check” under “Electric Throttle Body
Assembly On-Vehicle Inspection in Section 1C”.
Is output voltage within specified value?
Substitute a known-
good ECM and recheck.
Replace electric throttle
body.
Step Action Yes No
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