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 

   • Substitute with a known - good AFLS ECU or ECM/PCM and check for proper operation. If the problem is corrected, replace ECU and go to "VERIFICATION OF VEHICLE REPAIR " procedure.
     NOTE: * In case of replacing AFLS-ECU, perform following procedures.

     1. "Parameter Download" for initializing AFLS-ECU. (Refer to B1661 )
     2. "Calibration of Sensors" for height sensor calibration. (Refer to B1637 )

   NO 

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