Toyota Tundra Service Manual: Theft Deterrent System Communication Line High Fixation (B279A)

Toyota Tundra Service Manual / Vehicle Interior / Engine Immobiliser / Engine Immobiliser System (w/o Smart Key System) / Theft Deterrent System Communication Line High Fixation (B279A)

DESCRIPTION

When the communication line (EFIO-IMI) between the transponder key ECU assembly and ECM is stuck on HI output, the ECM stores this DTC.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Note

B279A

Theft Deterrent System Communication Line High Fixation

The communication line (EFIO-IMI) between the ECM and transponder key ECU assembly is stuck on HI output (1 trip detection logic*).

  • Harness or connector
  • ECM
  • Transponder key ECU assembly
  • Turn the ignition switch to ON and wait 6 seconds.
  • *: Only output while a malfunction is present.
Vehicle Condition and Fail-safe Operation when Malfunction Detected

Vehicle Condition when Malfunction Detected

Fail-safe Operation when Malfunction Detected

Engine cannot be started (initial ignition occurs and engine cranks, then ignition stops)

Engine cannot be started

Related Data List and Active Test

DTC No.

Data List and Active Test

B279A

-

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • If the transponder key ECU assembly or ECM is replaced, refer to Registration.

    Click here

  • After repair, confirm that no DTCs are output by performing "DTC Output Confirmation Operation".

PROCEDURE

1.

CHECK CONNECTION OF CONNECTOR

(a) Check that the connectors are properly connected to the ECM and transponder key ECU assembly.

OK:

Connectors are properly connected.

NG

CONNECT CONNECTORS PROPERLY

OK

2.

CHECK ECM (IMI TERMINAL VOLTAGE)

(a) Disconnect the transponder key ECU assembly connector.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

J26-13 (EFIO) - Body ground

Always

11 to 14 V

*a

Front view of wire harness connector

(to Transponder Key ECU Assembly)

(c) Connect the transponder key ECU assembly connector.

NG

GO TO STEP 4

OK

3.

CHECK TRANSPONDER KEY ECU ASSEMBLY (TERMINAL EFIO)

(a) Using an oscilloscope, check the waveform.

*a

Component with harness connected

(Transponder Key ECU Assembly)

*b

Waveform

Measurement Condition:

Item

Content

Tester Connection

J26-13 (EFIO) - Body ground

Tool Setting

2 V/DIV., 500 ms./DIV.

Condition

Within 3 seconds of starter operation and initial combustion, or within 3 seconds of ignition switch first being turned to ON after cable disconnected and reconnected to negative (-) battery terminal

OK:

Waveform is similar to that shown in the illustration.

OK (for 1UR-FE)

REPLACE ECM

OK (for 3UR-FE)

REPLACE ECM

OK (for 3UR-FBE)

REPLACE ECM

NG

REPLACE TRANSPONDER KEY ECU ASSEMBLY (TRANSPONDER KEY ECU ASSEMBLY WAS DEFECTIVE)

4.

CHECK HARNESS AND CONNECTOR (TRANSPONDER KEY ECU ASSEMBLY - ECM AND BODY GROUND)

(a) Disconnect the A24 ECM connector.

(b) Disconnect the J26 transponder key ECU assembly connector.

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

Standard Resistance:

for 1UR-FE

Tester Connection

Condition

Specified Condition

J26-13 (EFIO) - A24-40 (IMI)

Always

Below 1 Ω

A24-40 (IMI) - Body ground

Always

10 kΩ or higher

J26-13 (EFIO) - Body ground

Always

10 kΩ or higher

for 3UR-FE, 3UR-FBE

Tester Connection

Condition

Specified Condition

J26-13 (EFIO) - A24-46 (IMI)

Always

Below 1 Ω

A24-46 (IMI) - Body ground

Always

10 kΩ or higher

J26-13 (EFIO) - Body ground

Always

10 kΩ or higher

OK (for 1UR-FE)

REPLACE ECM

OK (for 3UR-FE)

REPLACE ECM

OK (for 3UR-FBE)

REPLACE ECM

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

    Engine Immobiliser System (w/o Smart Key System)

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