Toyota Venza manuals

Toyota Venza: Lost Communication with TCM (U0101)

Toyota Venza Service Manual / 1ar-fe Engine Control / Sfi System / Lost Communication with TCM (U0101)

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.

DTC No.

DTC Detection Condition

Trouble Area

U0101

  • Following conditions are met for 1.25 seconds
  • (1 trip detection logic):
    1. Ignition switch ON
    2. Battery voltage 10.5 V or more
    3. No intercommunication between ECM and TCM
  • ECM to TCM circuit
  • TCM
  • ECM

MONITOR STRATEGY

Related DTCs

U0101: Lost Communication with TCM

Required Sensors/Components (Main)

ECM

Required Sensors/Components (Related)

-

Frequency of Operation

Continuous

Duration

1.25 seconds

MIL Operation

Immediate

Sequence of Operation

None

TYPICAL ENABLING CONDITIONS

Monitor runs whenever following DTCs are not present

None

All of the following conditions are met

-

Battery voltage

10.5 V or more (More than 1 second)

Ignition switch

ON

Starter

Off

TYPICAL MALFUNCTION THRESHOLDS

Communication signal

Lost communication with TCM

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) (See page ).

  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.
  6. Wait 5 seconds or more.
  7. Enter the following menus: Powertrain / Engine / Trouble Codes.
  8. Read the Pending DTCs.

    HINT:

    • If a pending DTC is output, the system is malfunctioning.
    • If a pending DTC is not output, perform the following procedure.
  9. Enter the following menus: Powertrain / Engine / Utility / All Readiness.
  10. Input the DTC: U0101.
  11. Check the DTC judgment result.

    Techstream Display

    Description

    NORMAL

    • DTC judgment completed
    • System normal

    ABNORMAL

    • DTC judgment completed
    • System abnormal

    INCOMPLETE

    • DTC judgment not completed
    • Perform driving pattern after confirming DTC enabling conditions

    N/A

    • Unable to perform DTC judgment
    • Number of DTCs which do not fulfill DTC preconditions has reached ECU's memory limit

    HINT:

    • If the judgment result shows NORMAL, the system is normal.
    • If the judgment result shows ABNORMAL, the system has a malfunction.
  12. If the test result is INCOMPLETE or N/A and no pending DTC is output, perform a universal trip and check for permanent DTCs (See page ).

    HINT:

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

WIRING DIAGRAM


CAUTION / NOTICE / HINT

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 help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.

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: System Select / Health Check.

(e) Read the DTCs.

Result

Proceed to

DTC U0101 is output

A

DTC U0101 and other DTCs are output

B

HINT:

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


B

GO TO DTC CHART


A

2.

INSPECT ECU POWER SOURCE CIRCUIT (TCM POWER SOURCE)

(a) Disconnect the TCM connector.


(b) Turn the Ignition switch to ON.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

B40-1 (BATT) - B40-8 (E1)

Always

11 to 14 V

B40-18 (+B) - B40-8 (E1)

Ignition switch ON

11 to 14 V

Text in Illustration

*a

Front view of wire harness connector

(to TCM)

Result

Proceed to

OK

A

NG (for U760E)

B

NG (for U760F)

C


B

GO TO TCM POWER SOURCE CIRCUIT


C

GO TO TCM POWER SOURCE CIRCUIT


A

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):

Tester Connection

Condition

Specified Condition

B40-6 (CAN+) - B58-24 (CAN+)

Always

Below 1 Ω

B40-7 (CAN-) - B58-1 (CAN-)

Always

Below 1 Ω

Standard Resistance (Check for Short):

Tester Connection

Condition

Specified Condition

B40-6 (CAN+) or B58-24 (CAN+) - Body ground

Always

10 kΩ or higher

B40-7 (CAN-) or B58-1 (CAN-) - Body ground

Always

10 kΩ or higher

Result

Proceed to

OK (for U760E)

A

OK (for U760F)

B

NG

C


B

GO TO STEP 5


C

REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - TCM)


A

4.

REPLACE TCM

(a) Replace the TCM (for U760E) (See page
).


NEXT

GO TO STEP 6

5.

REPLACE TCM

(a) Replace the TCM (for U760F) (See page
).


NEXT

6.

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

Proceed to

DTC is not output

A

DTC U0101 is output

B


A

END


B

REPLACE ECM

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