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 Vehicle Repair" procedure.
NO
Go to "Signal Circuit Inspection" procedure.
Check for short to battery in signal harness
Ignition "OFF"
Disconnect ECT sensor connector.
Ignition "ON" & Engine "OFF".
Measure voltage between terminal 1 of the sensor harness connector and chassis ground
Specification : Approx. 5V
Is the measured voltage within specifications ?
YES
▶ Go to " Check for open in harness" as below.
NO
▶ Check for short to battery in signal harness.
Repair as necessary and go to "Verification vehicle Repair" procedure.
Check for open in harness
Ignition "OFF"
Disconnect ECT sensor connector
Ignition "ON" & Engine "OFF"
Measure resistance between terminal 1 of the sensor harness connector and terminal 3 of ECM harness connector.
Specification : Approx. below 1Ω
Is the measured resistance within specifications ?
YES
▶ Go to "Ground Circuit Inspection" procedure.
NO
▶ Check for open in signal harness.
Repair as necessary and go to "Verification of Vehicle Repair" procedure.
Ignition "OFF"
Disconnect ECT sensor connector and ECM connector.
Measure resistance between terminal 3 of the sensor harness connector and terminal 4 of ECM harness connector.
Specification : Approx. below 1Ω
Is the measured resistance within specifications ?
YES
▶ Go to "Component Inspection" procedure.
NO
▶ Check for open in harness.
Repair as necessary and go to "Verification of Vehicle Repair" procedure.
