W/Harness Inspection

Immobilizer
P1678 Immobilizer-EMS No Request ( EMS data line open, no immo.) - Inspection/Repair:_:W/Harness Inspection

Terminal and Connector Inspection

1. Many malfunctions in the electrical system are caused by poor harness(es) and terminals. Faults can also be caused by interference from other electrical systems and mechanical or chemical damage.
2. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
3. Has a problem been found ?






Power circuit Inspection

1. Ignition "OFF".
2. Disconnect ICU connector.
3. Ignition "ON" & Engine "OFF".
4. Measure voltage between Engine Control Relay Power of ICU harness connector and chassis ground.

Specification :B+








5. Is the measured voltage within specifications ?






Signal Circuit Inspection

Check for open in harness
1. Ignition "OFF".
2. Disconnect ICU and ECM/PCM connector.
3. Measure resistance between signal terminal of ICU harness connector and ECM/PCM harness connector.

Specification :1 Ohms or less








4. Is the measured voltage within specifications ?





Check for short in harness
1. Ignition "OFF".
2. Connect ICU connector.
3. Ignition "ON" & Engine "OFF".
4. Measure voltage between signal terminal of ICU harness connector and chassis ground.

Specification :Approx. 10V








5. Is the measured voltage within specifications ?