DTC U1800[86] CAN Communication or Input Data Malfunction With ECM

1. Electric power steering control system check

Refer to "56.Steering Control 6A.Troubleshooting diagnostic system check-electric power steering controls".

2. Current DTC check

1) Connect the scan tool.

2) Start the engine.

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 electric power steering control system.

Refer to "207.Steering 20D.Symptom intermittent conditions of electric power steering 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

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)".

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

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

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

1) Perform the Powertrain CAN communication circuit inspection and Chassis 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) chassis CAN communication circuit inspection".

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 EPS motor control unit replacement.

No

=>Go to Repair verification.

7. EPS motor control unit replacement

Refer to "6.Steering 6B.Power Assisted System power steering unit removal".

Refer to "6.Steering 6B.Power Assisted System power steering unit disassembly".

Refer to "6.Steering 6B.Power Assisted System power steering unit reassembly".

Refer to "6.Steering 6B.Power Assisted System power steering unit installation".

Refer to "6.Steering 6B.Power Assisted System power steering 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.