Diagnostic Trouble Code (DTC) U0001
High speed Can Communication
Conditions for Running the DTC
- Engine speed sensor revolution is 400rpm or greater.
- Input speed sensor revolution is 400rpm or greater.
- TCM receives "Bus OFF" state from CAN controller.
Conditions for Setting the DTC
- Above detection cumulatively occurs 7 times.
Action Taken When the DTC Sets
- TCM will request the illumination of MIL and store DTC when TCM detects a failure on the first ignition cycle.
- TCM judges the throttle opening is 0% for shift point and lock-up point control.
- TCM judges the throttle opening is 100% for line pressure control.
- No lock-up
- No self-learning control
- No 4th gear
- TCM judges the engine revolution is 0 rpm.
Conditions for Clearing the DTC
- The TCM turns off the MIL when no further failures detected for three consecutive ignition cycles.
- The scan tool can clear the DTC from the TCM history.
Cause of Failure
- Wiring harness or connector between ECM and TCM
- ECM
- TCM
DTC U0001 - High Speed CAN Communication
| Step | Action | Value(s) | Yes | No |
| 1 | - Turn the ignition OFF.
- Install the Scan tool.
- With the engine OFF, turn the ignition switch to the ON position.
- Select Store Freeze Frame/Failure Records from the Diagnostic Trouble Codes Information menu.
- Store Freeze Frame/Failure Records.
- Select Clear DTC Information from the Diagnostic Trouble Codes Information menu.
- Clear DTC Information.
- Perform one vehicle drive cycle.
Is the Malfunction Indicator Lamp (MIL) ON? | - | Go to Step 2 | Repair the temporary connection failure of connector. |
| 2 | - Select Request DTC by Status from the Diagnostic Trouble Codes Information menu.
- Request DTC by Status.
Is DTC U0001 displayed? | - | Go to Step 3 | Repair the temporary connection failure of connector. |
| 3 | - Turn the ignition OFF.
- Disconnect the TCM wiring connector and ECM wiring connector.
- Measure the resistance between terminal A17 of the TCM wiring connector and terminal K14 of the ECM wiring connector.
- Measure the resistance between terminal A7 of the TCM wiring connector and terminal K15 of the ECM wiring connector.
Is the resistance within the values shown? | 0 Ω | Go to Step 5 | Go to Step 4 |
| 4 | Repair the malfunctioning terminals as necessary. Is the action complete? | - | System OK | - |
| 5 | - Turn the ignition ON.
- Measure the voltage of terminal A17.
- Measure the voltage of terminal A7.
Is the voltage within the values shown? | 1.5-3.0 v | Go to Step 6 | Go to Step 7 |
| 6 | Repair the malfunctioning terminals as necessary. Is the action complete? | - | System OK | - |
| 7 | - Replace the TCM.
- Turn the ignition OFF.
- Turn the ignition ON.
- Check if U0001 DTC is set.
Is the DTC set? | - | Go to Step 8 | Go to Step 9 |
| 8 | Replace the ECM. Is the action complete? | - | Go to Step 9 | - |
| 9 | - After the repair, use a scan tool "clear info" function and road test the vehicle.
- Review the "DTC info".
Has the last test failed or is the current DTC displayed? | - | Begin diagnosis again | Repair verified exit DTC chart |
Diagnostic Trouble Code (DTC) U0100
Lost Communication with ECM/PCM
Conditions for Running the DTC
- The failure condition of CAN Bus OFF.
- Engine revolution is 400 rpm or greater.
- Input speed sensor revolution is 400 rpm or greater.
- TCM cannot detect ECM frame for 0.2 seconds continuously.
Conditions for Setting the DTC
- Above detection continuously occurs 10 times.
Action Taken When the DTC Sets
- TCM will request the illumination of MIL and store DTC when TCM detects a failure on the first ignition cycle.
- TCM judges the throttle opening is 0% for shift point and lock-up point control.
- TCM judges the throttle opening is 100% for line pressure control.
- No lock-up
- No self-learning control
- No 4th gear
- TCM judges the engine revolution is 0 rpm.
Conditions for Clearing the DTC
- The TCM turns off the MIL when no further failures detected for three consecutive ignition cycles.
- The scan tool can clear the DTC from the TCM history.
Cause of Failure
- Wiring harness or connector between ECM and TCM
- ECM
- TCM
DTC U0100 - Lost Communication with ECM/PCM
| Step | Action | Value(s) | Yes | No |
| 1 | - Turn the ignition OFF.
- Install the Scan tool.
- With the engine OFF, turn the ignition switch to the ON position.
- Select Store Freeze Frame/Failure Records from the Diagnostic Trouble Codes Information menu.
- Store Freeze Frame/Failure Records.
- Select Clear DTC Information from the Diagnostic Trouble Codes Information menu.
- Clear DTC Information.
- Perform one vehicle drive cycle.
Is the Malfunction Indicator Lamp (MIL) ON? | - | Go to Step 2 | Repair the temporary connection failure of connector. |
| 2 | - Select Request DTC by Status from the Diagnostic Trouble Codes Information menu.
- Request DTC by Status.
Is DTC U0100 displayed? | - | Go to Step 3 | Repair the temporary connection failure of connector. |
| 3 | - Turn the ignition OFF.
- Disconnect the TCM wiring connector and ECM wiring connector.
- Measure the resistance between terminal A17 of the TCM wiring connector and terminal K14 of the ECM wiring connector.
- Measure the resistance between terminal A7 of the TCM wiring connector and terminal K15 of the ECM wiring connector.
Is the resistance within the values shown? | 0 Ω | Go to Step 5 | Go to Step 4 |
| 4 | Repair the malfunctioning terminals as necessary. Is the action complete? | - | System OK | - |
| 5 | - Turn the ignition ON.
- Measure the voltage of terminal A17.
- Measure the voltage of terminal A7.
Is the voltage within the values shown? | 1.5-3.0 v | Go to Step 6 | Go to Step 7 |
| 6 | Repair the malfunctioning terminals as necessary. Is the action complete? | - | System OK | - |
| 7 | - Replace the TCM.
- Turn the ignition OFF.
- Turn the ignition ON.
- Check if U0100 DTC is set.
Is the DTC set? | - | Go to Step 8 | Go to Step 9 |
| 8 | Replace the ECM. Is the action complete? | - | Go to Step 9 | - |
| 9 | - After the repair, use a scan tool "clear info" function and road test the vehicle.
- Review the "DTC info".
Has the last test failed or is the current DTC displayed? | - | Begin diagnosis again | Repair verified exit DTC chart |
Diagnostic Trouble Code (DTC) U0401
Invalid Data Received from ECM/PCM
Conditions for Running the DTC
- Ignition voltage is greater than 9 volts.
- No failure condition of CAN Bus OFF.
- TCM receives engine speed signal for 0.2 seconds continuously.
Conditions for Setting the DTC
- Above detection continuously occurs 10 times.
Action Taken When the DTC Sets
- TCM will request the illumination of hold lamp.
- No lock-up
- No 4th gear
- No self-learning control
- No engine torque reduction control
- No engagement pressure control
- No timing solenoid control for N-D
- TCM judges that engine revolution is 0 rpm.
Conditions for Clearing the DTC
- The TCM turns off the hold lamp when no further failures detected for three consecutive ignition cycles.
- The scan tool can clear the DTC from the TCM history.
- The TCM clears the DTC from the TCM history memory after forty consecutive warm up cycles without fault.
- TCM receives the engine speed signal for 2 seconds.
Cause of Failure
- Wiring harness or connector between ECM and TCM
- ECM
- TCM
DTC U0401 - Invalid Data Received from ECM/PCM
| Step | Action | Value(s) | Yes | No |
| 1 | - Turn the ignition OFF.
- Install the Scan tool.
- With the engine OFF, turn the ignition switch to the ON position.
- Select Store Freeze Frame/Failure Records from the Diagnostic Trouble Codes Information menu.
- Store Freeze Frame/Failure Records.
- Select Clear DTC Information from the Diagnostic Trouble Codes Information menu.
- Clear DTC Information.
- Perform one vehicle drive cycle.
Is the Malfunction Indicator Lamp (MIL) ON? | - | Go to Step 2 | Repair the temporary connection failure of connector. |
| 2 | - Select Request DTC by Status from the Diagnostic Trouble Codes Information menu.
- Request DTC by Status.
Is DTC U0401 displayed? | - | Go to Step 3 | Repair the temporary connection failure of connector. |
| 3 | - Turn the ignition OFF.
- Disconnect the TCM wiring connector and ECM wiring connector.
- Measure the resistance between terminal A17 of the TCM wiring connector and terminal K14 of the ECM wiring connector.
- Measure the resistance between terminal A7 of the TCM wiring connector and terminal K15 of the ECM wiring connector.
Is the resistance within the values shown? | 0 Ω | Go to Step 5 | Go to Step 4 |
| 4 | Repair the malfunctioning terminals as necessary. Is the action complete? | - | System OK | - |
| 5 | - Turn the ignition ON.
- Measure the voltage of terminal A17.
- Measure the voltage of terminal A7.
Is the voltage within the values shown? | 1.5-3.0 v | Go to Step 6 | Go to Step 7 |
| 6 | Repair the malfunctioning terminals as necessary. Is the action complete? | - | System OK | - |
| 7 | - Replace the TCM.
- Turn the ignition OFF.
- Turn the ignition ON.
- Check if U0401 DTC is set.
Is the DTC set? | - | Go to Step 8 | Go to Step 9 |
| 8 | Replace the ECM. Is the action complete? | - | Go to Step 9 | - |
| 9 | - After the repair, use a scan tool "clear info" function and road test the vehicle.
- Review the "DTC info".
Has the last test failed or is the current DTC displayed? | - | Begin diagnosis again | Repair verified exit DTC chart |
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