THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function, HV Model): B279986; Engine Immobiliser System Signal (Some Circuit Quantity, Reported via Serial Data) Invalid; 2020 - 2022 MY Corolla Corolla HV [01/2019 - 09/2022]

Last Modified: 07-31-2024	6.11:8.1.0	Doc ID: RM100000001H8DO
Model Year Start: 2020	Model: Corolla	Prod Date Range: [01/2019 - 09/2022]
Title: THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function, HV Model): B279986; Engine Immobiliser System Signal (Some Circuit Quantity, Reported via Serial Data) Invalid; 2020 - 2022 MY Corolla Corolla HV [01/2019 - 09/2022]

DTC

B279986

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

DESCRIPTION

If there is a communication malfunction between the hybrid vehicle control ECU and ID code box (immobiliser code ECU), or when the communication ID codes do not match, the hybrid vehicle control ECU 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 hybrid vehicle control ECU and ID code box (immobiliser code ECU). The communication ID codes of the hybrid vehicle control ECU and ID code box (immobiliser code ECU) do not match.	ID code box (immobiliser code ECU) Hybrid vehicle control ECU Wire harness or connector	DTC output confirmation operation (Perform either of the following): Start the hybrid control system and wait for 10 seconds. If there is a malfunction, the hybrid control system will stop (communication begins within 3 seconds of the hybrid control system start operation being performed, and DTCs are stored after 6 seconds). Connect the cable to the negative (-) auxiliary battery terminal, start the hybrid control system and wait for 10 seconds (communication begins within 3 seconds of the power switch being turned on (IG), 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
Hybrid control system 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 Techstream with the power switch off, connect the Techstream to the DLC3 and turn a courtesy light switch on and off at intervals of 1.5 seconds or less until communication between the Techstream and the vehicle begins. Then select the vehicle type under manual mode and enter the following menus Body Electrical Smart Key. While using the Techstream, periodically turn a courtesy light switch on and off at intervals of 1.5 seconds or less to maintain communication between the Techstream 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 hybrid vehicle control ECU 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".

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 HYBRID VEHICLE CONTROL ECU (TERMINAL IMO)

(a) Using an oscilloscope, check the waveform.

*a

Component with harness connected

(Hybrid Vehicle Control ECU)

*b

Waveform

*c

Approximately 160 ms.

*d

Approximately 270 ms.

OK:

Tester Connection

Condition

Tool Setting

Specified Condition

I3-23 (IMO) - Body ground

Within 3 seconds of hybrid control system start or within 3 seconds of power switch turned on (IG) after cable disconnected and reconnected to auxiliary battery

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

Pulse generation

(See waveform)

Result	Proceed to
Normal waveform	A
Terminal EFII stuck low (2.4 V or less)	B
Waveform not output, or has abnormal wavelength or shape	C

B

C

A

3.	CHECK HYBRID VEHICLE CONTROL ECU (TERMINAL IMI)

(a) Using an oscilloscope, check the waveform.

*a

Component with harness connected

(Hybrid Vehicle Control ECU)

*b

Waveform

*c

Approximately 160 ms.

*d

Approximately 270 ms.

OK:

Tester Connection

Condition

Tool Setting

Specified Condition

I3-10 (IMI) - Body ground

Within 3 seconds of hybrid control system start or within 3 seconds of power switch turned on (IG) after cable disconnected and reconnected to auxiliary battery

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

Pulse generation

(See waveform)

NG

OK

4.	REGISTER ECU COMMUNICATION ID

(a) Register the ECU communication ID code.

Click here

NEXT

5.	CHECK WHETHER HYBRID CONTROL SYSTEM STARTS

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

(b) Check that the hybrid control system starts 5 seconds after the power switch turned on (IG).

OK:

Hybrid control system starts normally.

OK

END (ECU COMMUNICATION ID HAS NOT BEEN REGISTERED)

NG

REPLACE HYBRID VEHICLE CONTROL ECU

6.	CHECK HARNESS AND CONNECTOR (ID CODE BOX (IMMOBILISER CODE ECU) - HYBRID VEHICLE CONTROL ECU)

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

(b) Disconnect the I3 hybrid vehicle control ECU connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
I20-4 (EFIO) - I3-10 (IMI)	Always	Below 1 Ω
I20-4 (EFIO) or I3-10 (IMI) - Other terminals and body ground	Always	10 kΩ or higher

OK

REPLACE ID CODE BOX (IMMOBILISER CODE ECU)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

7.	CHECK HYBRID VEHICLE CONTROL ECU

(a) Disconnect the I3 hybrid vehicle control ECU connector.

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
I3-23 (IMO) - Body ground	Power switch turned on (IG) using registered electrical key transmitter sub-assembly	Terminal IMO stuck low (2.4 V or less)
I3-23 (IMO) - Body ground		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 HYBRID VEHICLE CONTROL ECU

A

8.	CHECK HARNESS AND CONNECTOR (ID CODE BOX (IMMOBILISER CODE ECU) - HYBRID VEHICLE CONTROL ECU)

(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) - I3-23 (IMO)	Always	Below 1 Ω
I20-3 (EFII) or I3-23 (IMO) - Other terminals and body ground	Always	10 kΩ or higher

OK

REPLACE ID CODE BOX (IMMOBILISER CODE ECU)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

9.	CHECK HARNESS AND CONNECTOR (ID CODE BOX (IMMOBILISER CODE ECU) - HYBRID VEHICLE CONTROL ECU)

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

(b) Disconnect the I3 hybrid vehicle control ECU connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
I20-3 (EFII) - I3-23 (IMO)	Always	Below 1 Ω
I20-3 (EFII) or I3-23 (IMO) - Other terminals and body ground	Always	10 kΩ or higher

OK

REPLACE HYBRID VEHICLE CONTROL ECU

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR