DTC U0100[00] Lost Communications with ECM (4WD models)

1. Transfer control system check

Refer to "53.Driveline Control 3A.Troubleshooting(4WD models) diagnostic system check-transfer case controls".

2. Prioritized DTC check

1) Connect the scan tool.

2) Turn OFF the ignition switch for 1 minute or more.

3) Start the engine.

4) Observe the DTC information with a scan tool. Is DTC U0046[88] set at the same time?

Yes

Go to DTC U0046[88] diagnosis.

Refer to "53.Driveline Control 3A.Troubleshooting(4WD models) DTC U0046[88] CAN Bus Off Error".

No

=>Go to ECM communication verification.

3. ECM communication verification

1) Check the communication status with the ECM using the scan tool. Can communication with the ECM be established?

Yes

=>Go to ECM-related DTC check.

No

Go to Lost communication with the ECM.

Refer to "51.Engine Control 1A.Troubleshooting(RZ4E-TC) 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 without radar sensor and 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(4JJ3 without DPD) lost communication with the ECM (models without radar sensor and stereo camera)".

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 with DPD) lost communication with the ECM (models without radar sensor and stereo camera)".

4. ECM-related DTC check

1) Observe the ECM-related DTC information on the scan tool. Is an ECM-related DTC set?

Yes

Go to the applicable DTC diagnosis.

No

=>Go to ECM harness connector inspection.

5. ECM harness connector inspection

1) Inspect for poor connections at the ECM harness connector. Is the connection status normal?

  • 4JJ3 engine models: ECM harness connector (pins 14 and 16 of C9)
  • RZ4E engine models: ECM harness connector (pins 58 and 78 of C7)

Refer to "LHD Controller Area Network (Central Gateway C/U)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "LHD Controller Area Network (Except Central Gateway C/U)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "RHD Controller Area Network (Central Gateway C/U (4JJ3 with DPD))" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "RHD Controller Area Network (Central Gateway C/U (4JJ3 without DPD, RZ4E))" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "RHD Controller Area Network (Except Central Gateway C/U)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Yes (Models with radar sensors)

=>Go to Central gateway control unit internal resistance inspection.

Yes (Models without radar sensors)

=>Go to Instrument panel cluster internal resistance inspection.

No

Repair the connections as necessary.

=>Go to Repair verification.

6. Central gateway control unit internal resistance inspection

1) Disconnect the central gateway control unit harness connector (B41).

2) Measure the resistance of the central gateway control unit harness connector (pins 5 and 6 of B41) with a DMM. Is the resistance within the specified range?

Refer to "LHD Controller Area Network (Central Gateway C/U)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "RHD Controller Area Network (Central Gateway C/U (4JJ3 with DPD))" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "RHD Controller Area Network (Central Gateway C/U (4JJ3 without DPD, RZ4E))" in the ETM (wiring diagram). (Open using the ETM viewer.).

Standard: 110 to 130 Ω

Yes

=>Go to ECM internal resistance inspection.

No

=>Go to Central gateway control unit replacement.

7. Instrument panel cluster internal resistance inspection

1) Disconnect the instrument panel cluster harness connector (B7).

2) Measure the resistance of the instrument panel cluster harness connector (pins 21 and 22 of B7) with a DMM. Is the resistance within the specified range?

Refer to "LHD Controller Area Network (Except Central Gateway C/U)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "RHD Controller Area Network (Except Central Gateway C/U)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Standard: 110 to 130 Ω

Yes

=>Go to ECM internal resistance inspection.

No

=>Go to Instrument panel cluster replacement.

8. ECM internal resistance inspection

1) Disconnect the ECM harness connector (C9).

2) Measure the resistance of the ECM harness connector (pins 14 and 16 of C9) with a DMM. Is the resistance within the specified range?

Refer to "LHD Controller Area Network (Central Gateway C/U)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "LHD Controller Area Network (Except Central Gateway C/U)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "RHD Controller Area Network (Central Gateway C/U (4JJ3 with DPD))" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "RHD Controller Area Network (Central Gateway C/U (4JJ3 without DPD, RZ4E))" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "RHD Controller Area Network (Except Central Gateway C/U)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Standard: 110 to 130 Ω

Yes

Repair the short to ground, short to the power supply circuit, open circuit, or the short together between the CAN Low circuit and the CAN High circuit between the TCCM and the ECM.

=>Go to Repair verification.

No

=>Go to ECM replacement.

9. ECM replacement

Note

  • Perform programming after replacing the ECM.

Refer to "1.Engine 1Z.Engine Electrical Control(RZ4E-TC) ECM removal".

Refer to "1.Engine 1Z.Engine Electrical Control(RZ4E-TC) ECM installation".

Refer to "1.Engine 1Z.Engine Electrical Control(RZ4E-TC) ECM setting".

Refer to "1.Engine 1Z.Engine Electrical Control(4JJ3 without DPD) ECM removal".

Refer to "1.Engine 1Z.Engine Electrical Control(4JJ3 without DPD) ECM installation".

Refer to "1.Engine 1Z.Engine Electrical Control(4JJ3 without DPD) ECM setting".

Refer to "1.Engine 1Z.Engine Electrical Control(4JJ3 with DPD) ECM removal".

Refer to "1.Engine 1Z.Engine Electrical Control(4JJ3 with DPD) ECM installation".

Refer to "1.Engine 1Z.Engine Electrical Control(4JJ3 with DPD) ECM setting".

Procedure completion

=>Go to Repair verification.

10. Central gateway control unit replacement

Note

  • Perform programming after replacing the central gateway control unit.

Refer to "9.Body, Cab, Accessories 9Z.Body, Cab, Accessories Electrical Control central gateway control unit removal".

Refer to "9.Body, Cab, Accessories 9Z.Body, Cab, Accessories Electrical Control central gateway control unit installation".

Refer to "9.Body, Cab, Accessories 9Z.Body, Cab, Accessories Electrical Control central gateway control unit setting".

Procedure completion

=>Go to Repair verification.

11. Instrument panel cluster replacement

Note

  • Perform programming after replacing the instrument panel cluster.

Refer to "9.Body, Cab, Accessories 9E.Instrumentation, Driver Info. instrument panel cluster removal".

Refer to "9.Body, Cab, Accessories 9E.Instrumentation, Driver Info. instrument panel cluster installation".

Refer to "9.Body, Cab, Accessories 9E.Instrumentation, Driver Info. instrument panel cluster setting".

Procedure completion

=>Go to Repair verification.

12. Repair verification

1) Clear the DTC with a scan tool.

2) Turn OFF the ignition switch for 1 minute or more.

3) Turn ON the ignition switch.

4) Observe the DTC information with a scan tool.