DTC U0100[00] Lost Communication With ECM (Auto A/C)

1. Auto A/C control system check

Refer to "57.HVAC Control 7A.Troubleshooting(Auto A/C) diagnostic system check-auto A/C controls".

2. Current DTC check

1) Connect the scan tool.

2) Turn ON the ignition switch.

3) Observe the DTC information with a scan tool. Is a DTC set?

Yes

=>Go to ECM communication verification.

No

Go to Intermittent conditions of auto A/C control system.

Refer to "208.HVAC 21D.Symptom intermittent conditions of auto A/C control system".

3. ECM communication verification

1) Use the scan tool to communicate with the ECM to display the data. Can communication with the ECM be established?

Yes

=>Go to ECM DTC check.

No (Models with radar sensors)

Go to Lost communication with the ECM.

Refer to "51.Engine Control 1A.Troubleshooting(4JJ3 with DPD) lost communication with the ECM (models with radar sensor/ stereo camera)".

Refer to "51.Engine Control 1A.Troubleshooting(4JJ3 without DPD) lost communication with the ECM (models with radar sensor/ stereo camera)".

Refer to "51.Engine Control 1A.Troubleshooting(RZ4E-TC) lost communication with the ECM (models with radar sensor/ stereo camera)".

No (Except models with radar sensors)

Go to Lost communication with the ECM.

Refer to "51.Engine Control 1A.Troubleshooting(4JJ3 with DPD) scan tool does not communicate with CAN device (models without radar sensor and stereo camera)".

Refer to "51.Engine Control 1A.Troubleshooting(4JJ3 without DPD) lost communication with the ECM (models without radar sensor and stereo camera)".

Refer to "51.Engine Control 1A.Troubleshooting(RZ4E-TC) lost communication with the ECM (models without radar sensor and stereo camera)".

4. ECM DTC check

1) Observe the ECM DTC information with a scan tool. Is a DTC set?

Yes

Go to the applicable DTC diagnosis.

No (Models with radar sensors)

=>Go to Powertrain CAN communication circuit inspection and Body CAN communication circuit inspection.

No (Except models with radar sensors)

=>Go to CAN communication circuit inspection.

5. Powertrain CAN communication circuit inspection and Body CAN communication circuit inspection

1) Perform powertrain CAN communication circuit inspection and body CAN communication circuit inspection.

Refer to "64.Body Control 10I.Troubleshooting(Central GateWay) powertrain CAN communication circuit inspection".

Refer to "64.Body Control 10I.Troubleshooting(Central GateWay) body CAN communication circuit inspection".

Procedure completion

=>Go to Current DTC follow-up check.

6. CAN communication circuit inspection

1) Perform Scan tool does not communicate with CAN device.

Refer to "51.Engine Control 1A.Troubleshooting(4JJ3 with DPD) scan tool does not communicate with CAN device (models without radar sensor and stereo camera)".

Refer to "51.Engine Control 1A.Troubleshooting(4JJ3 without DPD) scan tool does not communicate with CAN device (models without radar sensor and stereo camera)".

Refer to "51.Engine Control 1A.Troubleshooting(RZ4E-TC) scan tool does not communicate with CAN device (models without radar sensor and stereo camera)".

Procedure completion

=>Go to Current DTC follow-up check.

7. Current DTC follow-up check

1) Clear the DTC with a scan tool.

2) Turn OFF the ignition switch.

3) Turn ON the ignition switch.

4) Observe the DTC information with a scan tool.

Yes

=>Go to Control panel replacement.

No

=>Go to Repair verification.

8. Control panel replacement

Refer to "7.HVAC 7B.Heater Ventilator Airconditioner control panel and control lever removal".

Refer to "7.HVAC 7B.Heater Ventilator Airconditioner control panel and control lever installation".

Refer to "7.HVAC 7B.Heater Ventilator Airconditioner control panel and control lever setting".

Procedure completion

=>Go to Repair verification.

9. Repair verification

1) Clear the DTC with a scan tool.

2) Turn OFF the ignition switch.

3) Turn ON the ignition switch.

4) Observe the DTC information with a scan tool.