1A-82 Engine General Information and Diagnosis:
4 ECM voltage 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-
24” terminal.
4) If OK, then turn ON ignition switch, measure voltage
between “C37-24” wire terminal of ECM connector and
vehicle body ground.
Is voltage about 4 – 6 V?
“LT GRN” wire is open
circuit. If wire and
connection are OK, go
to Step 5.
Go to Step 5.
5 ECT sensor harness voltage check
1) Disconnect connectors from ECM with ignition switch
turned OFF.
2) Turn ON ignition switch.
3) Measure voltage between “LT GRN” wire terminal of
ECT sensor connector and vehicle body ground.
Is voltage about 0 V?
Go to Step 6. “LT GRN” wire is
shorted to other circuit.
If wire is OK, substitute
a known-good ECM and
recheck.
6 ECT sensor harness resistance check
1) Measure resistance between “C37-24” terminal of ECM
connector and “LT GRN” wire terminal of ECT sensor
connector with ignition switch turn OFF.
Is resistance below 5
Ω
?
Go to Step 7. “LT GRN” wire is high
resistance circuit.
7 ECT sensor ground circuit check
1) Connect connectors to ECM.
2) Check for proper connection of ECT sensor connector at
“ORN” wire terminal.
3) Measure resistance between “ORN” wire terminal of
ECT sensor connector and vehicle body ground.
Is resistance below 5
Ω
?
Go to Step 9. Go to Step 8.
8 ECT sensor ground circuit check
1) Measure resistance between “C37-55” terminal of ECM
connector and vehicle body ground.
Is resistance below 5
Ω
?
“ORN” wire is open
circuit or high resistance
circuit. Poor “C37-55”
connection.
Faulty ECM ground
circuit. If circuit is OK,
substitute a known-
good ECM and recheck.
9 ECT sensor for performance check
1) Check ECT sensor according to “ECT Sensor Inspection
in Section 1C”.
Is it in good condition?
Substitute a known-
good ECM and recheck.
Replace ECT sensor.
Step Action Yes No
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