CAN communication circuit inspection (AFLS ECU ↔ ECM/PCM)

■ Open in circuit check 

1. Ignition "OFF"
2. Disconnect ECM/PCM connector and AFLS ECU connector
3. Measure the resistance between CAN-HIGH terminal of ECM/PCM harness connector and CAN-HIGH terminal of AFLS ECU harness connector.
4. Measure the resistance between CAN-LOW terminal of ECM/PCM harness connector and CAN-LOW terminal of AFLS ECU harness connector.

   Specification:  below 1Ω

■ Short in circuit check 

1. Ignition "OFF"
2. Disconnect AFLS-ECU connector.
3. Measure the voltage between CAN-HIGH terminal of AFLS-ECU and chassis ground.
4. Measure the voltage between CAN-LOW terminal of AFLS-ECU and chassis ground.

   Specification:  Approx. 0V

5. Ignition "OFF"
6. Disconnect AFLS-ECU connector.
7. Measure the resistance between CAN-HIGH terminal of AFLS-ECU and chassis ground.
8. Measure the resistance between CAN-LOW terminal of AFLS-ECU and chassis ground.

   Specification:  ∞Ω

9. Is the measured values within specification?

   YES 

   • Go to "COMPONENT INSPECTION " procedure.

   NO 

   • Check for open/short in harness.
   • Repair as necessary and then go to "VERIFICATION OF VEHICLE REPAIR " procedure.