U0101
2GR-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: U0101: Lost Communication with TCM
U0101 - Lost Communication with TCM
DESCRIPTION
The TCM and ECM perform 2-way communications with each other via the Controller Area Network (CAN). The TCM sends signals to the ECM concerning required engine rpm, required engine torques, warning indicators in the combination meter, DTCs and other data. The ECM sends signals to the TCM concerning engine rpm, opening angles of the throttle valve, temperature of intake air, temperature of engine coolant, engine torques 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 engine switch on (IG) 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 engine switch off and wait for 30 seconds.
5. Turn the engine switch on (IG) and turn the Techstream on.
6. Wait 5 seconds or more.
7. Enter the following menus: Powertrain / Engine / Trouble Codes.
8. Read the DTC.
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.
13. If the test result is INCOMPLETE or N/A and no 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
NOTICE:
Inspect the fuses for circuits related to this system before performing the following inspection procedure.
HINT
Read freeze frame data using the Techstream. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air-fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction Freeze Frame Data.
PROCEDURE
1. CHECK OTHER DTC 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 the DTCs.
Result:
B -- GO TO DTC CHART SFI System
A -- Continue to next step.
2. CHECK TCM TERMINAL VOLTAGE (+B AND E1 OR BATT AND E1 TERMINALS)
(a) Disconnect the B40 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) Turn the engine switch off.
(e) Measure the resistance according to the value(s) in the table below.
Standard resistance (check for open):
(f) Reconnect the TCM connector.
NG -- GO TO TCM POWER SOURCE CIRCUIT
OK -- Continue to next step.
3. CHECK HARNESS AND CONNECTOR
(a) Disconnect the B40 TCM connector.
(b) Disconnect the B12 ECM connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:
(d) Reconnect the TCM connector.
(e) Reconnect the ECM connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
4. REPLACE TCM
(a) Replace the TCM Removal.
NEXT -- Continue to next step.
5. CHECK IF DTC RECURS
(a) Connect Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Turn the Techstream on.
(d) Clear the DTCs.
(e) Turn the engine switch off.
(f) Turn the engine switch on (IG) and turn the Techstream on.
(g) Wait 5 seconds or more.
(h) Enter the following menus: Powertrain / Engine / Trouble Codes.
(i) Read the DTCs.
Result:
B -- END
A -- REPLACE ECM Removal