DTC U1840[86] BCM Communication Interruption/Data Malfunction (eCall unit)

1. Body control system check

Refer to "64.Body Control 10I.Troubleshooting(eCall unit) diagnostic system check - emergency call system 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 BCM communication verification.

No

Go to Intermittent conditions of body control system.

Refer to "223.Body Control 36D.Symptom(eCall unit) intermittent conditions of body control system".

3. BCM communication verification

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

Yes

=>Go to BCM DTC check.

No

Go to Lost communication with the BCM.

Refer to "64.Body Control 10I.Troubleshooting(BCM) lost communication with the BCM (models without radar sensor and stereo camera)".

4. BCM DTC check

1) Observe the BCM DTC information on the scan tool. Is a DTC set?

Yes

Go to the applicable DTC diagnosis.

No

=>Go to CAN communication circuit inspection.

5. CAN communication circuit inspection

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

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.

6. Current DTC follow-up check

1) Clear the DTC with a scan tool.

2) Turn OFF the ignition switch for 30 seconds or more.

3) Turn ON the ignition switch.

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

Yes

=>Go to eCall unit replacement.

No

=>Go to Repair verification.

7. eCall unit replacement

Refer to "9.Body, Cab, Accessories 9Z.Body, Cab, Accessories Electrical Control eCall unit removal".

Refer to "9.Body, Cab, Accessories 9Z.Body, Cab, Accessories Electrical Control eCall unit installation".

Refer to "9.Body, Cab, Accessories 9Z.Body, Cab, Accessories Electrical Control eCall unit setting".

Procedure completion

=>Go to Repair verification.

8. Repair verification

1) Clear the DTC with a scan tool.

2) Turn OFF the ignition switch for 30 seconds or more.

3) Turn ON the ignition switch.

4) Observe the DTC information with a scan tool.