Many malfunctions in the electrical system are caused by poor harness and terminals.
Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
Has a problem been found?
YES
▶ Repair as necessary and go to "Verification of Vehicle Repair" procedure.
NO
▶ Go to "Signal Circuit Inspection " procedure.
Check reference voltage to ECT sensor.
Ignition "OFF"
Disconnect ECT sensor connector
Ignition "ON" & Engine"OFF"
Measure voltage between terminal 1 of the ECT sensor harness connector and chassis ground.
Specification : Approx. 5V
Is the measured voltage within specifications ?
YES
▶ Go to "Ground circuit inspection" procedure.
NO
▶ Go to "Check for open in harness" as below
Check for open in harness
Ignition "OFF"
Disconnect ECT connector
Measure resistance between terminal "1" of ECT sensor harness connector and 4 of the PCM harness connector.
Specification : Approx. below 0Ω
Is the measured resistance within specifications ?
YES
▶ Go to "Check for short to ground" in harness procedure.
NO
▶ Repair or replace as necessary. And then, go to "Verification of Vehicle Repair" procedure.
Check for short to ground in harness
Ignition "OFF"
Disconnect ECT connector
Measure resistance between terminal 1 of the ECT sensor harness connector and chassis ground.
Specification : Infinite
Is the measured resistance within specifications ?
YES
▶ Go to "Check for short to battery in harness" procedure.
NO
▶ Repair or replace as necessary and then go to "Verification of Vehicle Repair" procedure.
Check for short to battery in harness
Ignition "ON" & engine "OFF"
Disconnect ECT connector.
Measure voltage between terminal 1 of the ECT sensor harness connector and chassis ground.
Specification : Approx. 0V
Is the measured voltage within specification ?
YES
▶ Go to "Ground circuit inspection" procedure.
NO
▶ Check for short to ground in harness
▶ Repair or replace as necessary and then, go to "Verification of Vehicle Repair" procedure.
Check for open in harness
Ignition "ON" & engine "OFF"
Disconnect ECT connector.
Connect jumper wire between terminals 1 and 3 of the ECT sensor harness connector.
Specification : Approx. 0V (120 ℃)
Is the measured voltage within specifications ?
YES
▶ Go to "Component Inspection " procedure.
NO
▶ Repair or replace as necessary. And then, go to "Verification of Vehicle Repair" procedure.
