SFI System

2GR-FE ENGINE CONTROL: SFI SYSTEM: U0101: Lost Communication with TCM
U0101 - Lost Communication with TCM

DESCRIPTION

The Transmission Control Module (TCM) and ECM perform 2-way communication with each other via the Controller Area Network (CAN). The TCM sends signals to the ECM concerning required engine speed, required engine torque, warning indicators in the combination meter, DTCs and other data. The ECM sends signals to the TCM concerning engine speed, opening angle of the throttle valve, temperature of intake air, temperature of engine coolant, engine torque and other data. If the TCM cannot communicate with the ECM, the TCM will conclude that there is a malfunction in the CAN system, illuminate the MIL and set a DTC.





MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS





TYPICAL MALFUNCTION THRESHOLDS





CONFIRMATION DRIVING PATTERN





1. Connect the Techstream to the DLC3.

2. Turn the ignition switch to ON and turn the Techstream on.

3. Clear the DTCs (even if no DTCs are stored, perform the Clear DTC procedure) Reading and Clearing Diagnostic Trouble Codes.

4. Turn the ignition switch off and wait for at least 30 seconds.

5. Turn the ignition switch to ON and turn the Techstream on [A].

6. Wait 5 seconds or more.

7. Enter the following menus: Powertrain / Engine / Trouble Codes.

8. Read the DTC [B].

9. If a DTC is output, the system is malfunctioning.

HINT
If a DTC is not output, perform the following procedure.

10. Enter the following menus: Powertrain / Engine / Utility / All Readiness.

11. Input the DTC: U0101.

12. Check the DTC judgment result.





HINT
* If the judgment result shows ABNORMAL, the system has a malfunction.
* If the judgment result shows NORMAL, the system is normal.
* If the judgment result shows INCOMPLETE or N/A, perform step [B] again.

13. Enter the following menus: Powertrain / Engine / Utility / All Readiness.

14. Check the judgment result.

HINT
* If the judgment result shows ABNORMAL, the system has a malfunction.
* If the judgment result shows NORMAL, the system is normal.

15. If the test result is INCOMPLETE or N/A and no pending DTC is output, perform a universal trip and check for permanent DTCs Reading and Clearing Diagnostic Trouble Codes.

HINT
* If a permanent DTC is output, the system is malfunctioning.
* If no permanent DTC is output, the system is normal.

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. CHECK OTHER DTC OUTPUT (IN ADDITION TO DTC U0101)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine / Trouble Codes.

(e) Read the DTCs.

Result:





HINT
If any DTCs other than U0101 are output, troubleshoot those DTCs first.

B -- GO TO DTC CHART SFI System
A -- Continue to next step.

2. INSPECT ECU POWER SOURCE CIRCUIT (TCM POWER SOURCE)

(a) Disconnect the TCM connector.





(b) Turn the Ignition switch to ON.

(c) Measure the resistance according to the value(s) in the table below.

Standard Voltage:





Text in Illustration





(d) Reconnect the TCM connector.

NG -- GO TO TCM POWER SOURCE CIRCUIT ECU Power Source Circuit
OK -- Continue to next step.

3. CHECK HARNESS AND CONNECTOR (ECM - TCM)

(a) Disconnect the TCM connector.

(b) Disconnect the ECM connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance (Check for Open):





Standard Resistance (Check for Short):





(d) Reconnect the ECM connector.

(e) Reconnect the TCM connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - TCM)
OK -- Continue to next step.

4. REPLACE ECM

(a) Replace the ECM Removal.

NEXT -- Continue to next step.

5. CHECK WHETHER DTC OUTPUT RECURS (DTC U0101)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine / Trouble Codes.

(e) Read the DTCs.

Result:





B -- REPLACE TCM Removal

A -- END