DTC U1821[86] Invalid Data Received from ABS (Wireless Access Module (Hi-version [Passive Entry and Start System]))

1. Wireless access module system check

Refer to "71.Security and Locks Control 10S.Troubleshooting(Wireless Access Module (Hi-version [Passive Entry and Start System])) Diagnostic system check-Wireless Access Module (Hi-version[Passive Entry and Start System])".

2. Wireless access module DTC check

1) Observe whether a DTC is set in the wireless access module on the scan tool. Is a DTC set in the wireless access module?

Yes

=>Go to EHCU communication verification.

No

Go to Intermittent conditions of wireless access module.

Refer to "229.Security and Locks Control 42D.Symptom intermittent conditions of wireless access module".

3. EHCU communication verification

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

Yes

=>Go to EHCU DTC check.

No (Models with radar sensors/stereo cameras)

Refer to "54.Brake Control 4A.Troubleshooting(ABS/ESC) lost communication with the EHCU (models with radar sensor/ stereo camera)".

No (Models without radar sensors and stereo cameras)

Refer to "54.Brake Control 4A.Troubleshooting(ABS/ESC) lost communication with the EHCU (models without radar sensor and stereo camera)".

4. EHCU DTC check

1) Observe whether a DTC is set in the EHCU on the scan tool. Is a DTC set in the EHCU?

Yes

Go to the applicable DTC diagnosis.

No (Models with radar sensors/stereo cameras)

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

No (Models without radar sensors and stereo cameras)

=>Go to CAN communication system inspection.

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

1) Perform Chassis CAN communication circuit inspection and Body CAN communication circuit inspection.

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

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

Procedure completion

=>Go to Current DTC check.

6. CAN communication system inspection

1) Inspect the CAN communication system.

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)".

Procedure completion

=>Go to Current DTC check.

7. Current DTC check

1) Turn OFF the ignition switch.

2) Turn ON the ignition switch.

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

Yes

=>Go to Wireless access module replacement.

No

=>Go to Repair verification.

8. Wireless access module replacement

Refer to "9.Body, Cab, Accessories 9Z.Body, Cab, Accessories Electrical Control wireless access module removal".

Refer to "9.Body, Cab, Accessories 9Z.Body, Cab, Accessories Electrical Control wireless access module installation".

Refer to "9.Body, Cab, Accessories 9Z.Body, Cab, Accessories Electrical Control wireless access module setting (with passive entry and start system)".

Procedure completion

=>Go to Repair verification.

9. Repair verification

1) Connect all of the disconnected harness connectors.

2) Clear the DTC with a scan tool.

3) Turn OFF the ignition switch.

4) Turn ON the ignition switch and wait for 5 seconds or more.

5) Observe the DTC information with a scan tool.