Toyota Corolla Cross Owners & Service Manuals

Toyota Corolla Cross: Engine Immobiliser System Signal (Some Circuit Quantity, Reported via Serial Data) Invalid (B279986)

Toyota Corolla Cross (2022-2024) Service Manual / Vehicle Interior / Theft Deterrent / Keyless Entry / Smart Key System (for Start Function, Gasoline Model) / Engine Immobiliser System Signal (Some Circuit Quantity, Reported via Serial Data) Invalid (B279986)

DESCRIPTION

If there is a communication malfunction between the ECM and ID code box (immobiliser code ECU), or when the communication ID codes do not match, the ECM stores this DTC.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Note

B279986

Engine Immobiliser System Signal (Some Circuit Quantity, Reported via Serial Data) Invalid

Either of the following conditions is met (1 trip detection logic*):

  • A malfunction is detected in the communication or communication lines between the ECM and ID code box (immobiliser code ECU).
  • The communication ID codes of the ECM and ID code box (immobiliser code ECU) do not match.
  • ID code box (immobiliser code ECU)
  • ECM
  • Wire harness or connector

DTC output confirmation operation (Perform either of the following):

  • Start the engine and wait for 10 seconds. If there is a malfunction, the engine will stop (communication begins within 3 seconds of the engine start operation being performed, and DTCs are stored after 6 seconds).
  • Connect the cable to the negative (-) auxiliary battery terminal, start the engine and wait for 10 seconds (communication begins within 3 seconds of the ignition switch being turned to ON, and DTCs are stored after 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

-
Related Data List and Active Test

DTC No.

Data List and Active Test

B279986

-

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • When using the GTS with the ignition switch off, connect the GTS to the DLC3 and turn a courtesy light switch on and off at intervals of 1.5 seconds or less until communication between the GTS and the vehicle begins. Then select the vehicle type under manual mode and enter the following menus: Body Electrical / Smart Key. While using the GTS, periodically turn a courtesy light switch on and off at intervals of 1.5 seconds or less to maintain communication between the GTS and the vehicle.
  • The smart key system (for Start Function) uses the LIN communication system and CAN communication system. Inspect the communication function by following How to Proceed with Troubleshooting. Troubleshoot the smart key system (for Start Function) after confirming that the communication systems are functioning properly.

    Click here

  • Before replacing the ECM or ID code box (immobiliser code ECU), refer to Registration.

    Click here

  • After performing repairs, confirm that no DTCs are output by performing "DTC Output Confirmation Operation".
  • When the ECM is replaced, update the ECU security key.

    Click here

HINT:

When DTC B279986 and the certification ECU (smart key ECU assembly) DTC are output simultaneously, first perform troubleshooting for the certification ECU (smart key ECU assembly) DTC.

PROCEDURE

1.

REGISTER ECU COMMUNICATION ID

(a) Register the ECU communication ID code.

Click here

NEXT

2.

CHECK ECM (TERMINAL EFII)

(a) Using an oscilloscope, check the waveform.

*a

Component with harness connected

(ID Code Box (Immobiliser Code ECU))

*b

Waveform

*c

Approximately 160 ms.

*d

Approximately 270 ms.

OK:

Tester Connection

Switch Condition

Tool Setting

Specified Condition

I20-3 (EFII) - Body ground

Ignition switch ON

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

Pulse generation

(See waveform)

Result

Proceed to

Normal waveform

A

Terminal IMO stuck low (2.4 V or less)

B

Waveform not output, or has abnormal wavelength or shape

C
B

GO TO STEP 6

C

REPLACE ECM

A

3.

CHECK ID CODE BOX (IMMOBILISER CODE ECU) (TERMINAL EFIO)

(a) Using an oscilloscope, check the waveform.

*a

Component with harness connected

(ID Code Box (Immobiliser Code ECU))

*b

Waveform

*c

Approximately 160 ms.

*d

Approximately 270 ms.

Measurement Condition:

Tester Connection

Condition

Tool Setting

Specified Condition

I20-4 (EFIO) - Body ground

Ignition switch turned ON using registered electrical key transmitter sub-assembly

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

Pulse generation

(See waveform)
NG

REPLACE ID CODE BOX (IMMOBILISER CODE ECU)

OK

4.

REGISTER ECU COMMUNICATION ID

(a) Register the ECU communication ID code.

Click here

NEXT

5.

CHECK WHETHER ENGINE STARTS

(a) Using an electrical key transmitter sub-assembly which is registered to the vehicle, turn the ignition switch to ON.

(b) Check that the engine starts 5 seconds after the ignition switch turned to ON.

OK:

Engine starts normally.

OK

END (ECU COMMUNICATION ID HAS NOT BEEN REGISTERED)
NG

REPLACE ECM

6.

CHECK ECM

(a) Disconnect the A47 ECM connector.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

A47-25 (IMO) - Body ground

Ignition switch turned to ON using registered electrical key transmitter sub-assembly

Terminal IMO stuck low (2.4 V or less)

Terminal IMO stuck high (12 V) or abnormal waveform

Result

Proceed to

Terminal IMO stuck low (2.4 V or less)

A

Terminal IMO stuck high (12 V) or abnormal waveform

B
B

REPLACE ECM

A

7.

CHECK HARNESS AND CONNECTOR (ID CODE BOX (IMMOBILISER CODE ECU) - ECM)

(a) Disconnect the I20 ID code box (immobiliser code ECU) connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

I20-3 (EFII) - Other terminals and body ground

Always

10 kΩ or higher

I20-4 (EFIO) - Other terminals and body ground

Always

10 kΩ or higher
OK

REPLACE ID CODE BOX (ID CODE BOX)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

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