1UR-FSE Engine Control System: SFI System

1UR-FSE ENGINE CONTROL SYSTEM: SFI SYSTEM: U0101: Lost Communication with TCM

DTC U0101 - Lost Communication with TCM

DESCRIPTION

The ECM (engine control unit) intercommunicates with the TCM (transmission control ECU) through the Controller Area Network (CAN).
If there is a problem in this intercommunication, the ECM sets a DTC.






MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS





TYPICAL MALFUNCTION THRESHOLDS





WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC U0101)
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Turn the Techstream ON.
(d) Enter the following menus: Powertrain / Engine / Trouble Codes.
(e) Read DTCs.
Result:





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

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

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




(a) Disconnect the TCM connector.
(b) Turn the engine switch on (IG).
(c) Measure the voltage according to the value(s) in the table below.
Standard voltage:





(d) Reconnect the TCM connector.
NG -- GO TO TCM POWER SOURCE CIRCUIT
OK -- Continue to next step.

3. CHECK HARNESS AND CONNECTOR (ECM - TCM)




(a) Disconnect the ECM connector.
(b) Disconnect the TCM 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 and TCM connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

4. REPLACE ECM
(a) Replace the ECM Components.
NEXT -- Continue to next step.

5. CHECK WHETHER DTC OUTPUT RECURS (DTC U0101)
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG) and turn the Techstream ON.
(c) Enter the following menus: Powertrain / Engine / Trouble Codes.
(d) Read DTCs.
Result:






B -- REPLACE TCM
A -- END