Toyota Avalon (XX50): System Voltage or GND Energization Malfunction (B228B). Short to GND in Immobiliser System Power Source Circuit (B278A). Malfunction of ID-BOX Recognition (B278D)

Toyota Avalon (XX50) 2019-2022 Service & Repair Manual / Vehicle Interior / Theft Deterrent / Keyless Entry / Smart Key System(for Start Function, Gasoline Model) / System Voltage or GND Energization Malfunction (B228B). Short to GND in Immobiliser System Power Source Circuit (B278A). Malfunction of ID-BOX Recognition (B278D)

System Voltage or GND Energization Malfunction (B228B)

SYSTEM DESCRIPTION

This DTC is stored when there is a malfunction in the certification ECU (smart key ECU assembly) battery power supply circuit or ground circuit.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Note

B228B

System Voltage or GND Energization Malfunction

A malfunction is detected in the certification ECU (smart key ECU assembly) battery power supply circuit or ground circuit. (1-trip detection logic*)
  • AM2 fuse
  • Wire harness or connector
  • Drive the vehicle.
  • *: Only detected while a malfunction is present.
Vehicle Condition and Fail-safe Function when Malfunction Detected

Vehicle Condition when Malfunction Detected

Fail-safe Function when Malfunction Detected

The engine stopped while driving.

-
Related Data List and Active Test Items

DTC No.

Data List and Active Test

B228B

-

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • When using the Techstream with the engine 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, Gasoline Model) 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, Gasoline Model) after confirming that the communication systems are functioning properly.

    Click here

  • Inspect the fuses of circuits related to this system before performing the following procedure.
  • After repair, confirm that no DTCs are output by performing "DTC Output Confirmation Operation".

PROCEDURE

1.

CHECK HARNESS AND CONNECTOR (POWER SOURCE)

(a) Disconnect the G40 certification ECU (smart key ECU assembly) connector.

*a

Front view of wire harness connector

(to Certification ECU (Smart Key ECU Assembly))

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

G40-4 (+B) - Body ground

Always

11 to 14 V
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR IN CIRCUIT CONNECTED TO POWER SOURCE
OK

2.

CHECK HARNESS AND CONNECTOR (GROUND)

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

G40-18 (E) - Body ground

Always

Below 1 Ω

*a

Front view of wire harness connector

(to Certification ECU (Smart Key ECU Assembly))
OK

END (TEMPORARY CONNECTION FAILURE IS SUSPECTED)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR IN CIRCUIT CONNECTED TO POWER SOURCE

Short to GND in Immobiliser System Power Source Circuit (B278A)

DESCRIPTION

When there is a short to GND in the power supply for the transponder key amplifier of the engine switch, the certification ECU (smart key ECU assembly) stores this DTC.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Note

B278A

Short to GND in Immobiliser System Power Source Circuit

A short to GND in the power supply of the transponder key amplifier of the engine switch (VC5 - VC5) detected. (1 trip detection logic*)
  • Engine switch
  • Certification ECU (smart key ECU assembly)
  • Wire harness or connector

DTC output confirmation operation:

  • With the shift lever in P and the electrical key transmitter sub-assembly held near the engine switch, an engine start operation is performed by pressing and holding the engine switch when the transmitter battery is depleted.
  • *: 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 when transmitter battery is depleted by holding transmitter near engine switch and pressing and holding engine switch with shift lever in P

-
Related Data List and Active Test

DTC No.

Data List and Active Test

B278A

-

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • When using the Techstream with the engine 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, Gasoline Model) 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, Gasoline Model) after confirming that the communication systems are functioning properly.

    Click here

  • Before replacing the certification ECU (smart key ECU assembly), refer to Registration.

    Click here

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

PROCEDURE

1.

CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

(a) Using an oscilloscope, check the waveform.

*a

Component with harness connected

(Engine Switch)

-

-

HINT:

Perform this inspection on the engine switch side.

Measurement Condition:

Tester Connection

Condition

Tool Setting

Specified Condition

G41-10 (VC5) - G41-6 (AGND)

Engine switch off, electrical key transmitter sub-assembly not in cabin, within 30 seconds of engine switch pressed

2 V/DIV., 200 ms./DIV.

Pulse generation

OK:

The waveform is similar to that shown in the illustration.

OK

REPLACE ENGINE SWITCH

NG

2.

CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - ENGINE SWITCH)

(a) Disconnect the G40 certification ECU (smart key ECU assembly) connector.

(b) Disconnect the G41 engine switch connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

G40-7 (VC5) - G41-10 (VC5)

Always

Below 1 Ω

G40-11 (AGND) - G41-6 (AGND)

Always

Below 1 Ω

G40-7 (VC5) or G41-10 (VC5) - Other terminals and body ground

Always

10 kΩ or higher

G40-11 (AGND) or G41-6 (AGND) - Other terminals and body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

3.

CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

(a) Connect the G40 certification ECU (smart key ECU assembly) connector.

(b) Connect the G41 engine switch connector.

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

*a

Component with harness connected

(Certification ECU (Smart Key ECU Assembly))

-

-

Standard Voltage:

Tester Connection

Condition

Specified Condition

G40-7 (VC5) - G40-11 (AGND)

Engine switch off, brake pedal not depressed, 30 seconds or more after driver door opened and then closed

Below 1 V
OK

REPLACE ENGINE SWITCH

NG

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

Malfunction of ID-BOX Recognition (B278D)

DESCRIPTION

When the certification ECU (smart key ECU assembly) detects an input signal indicating that the vehicle is equipped with an ID code box even though the ID code box is not registered, the certification ECU (smart key ECU assembly) stores this DTC.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Note

B278D

Malfunction of ID-BOX Recognition

One of the following conditions is met:

  • The certification ECU (smart key ECU assembly) recognizes that the wire harness judging whether the vehicle is equipped with an ID code box or not is provided even though the ID code box is not registered.
  • The certification ECU (smart key ECU assembly) receives a LIN signal from the ID code box even though the ID code box is not registered.
  • The certification ECU (smart key ECU assembly) receives a LIN signal from the ID code box even though the wire harness judging whether the vehicle is equipped with an ID code box or not is not provided.

Misconnection of the ID code box

DTC output confirmation operation:

  • Always
Vehicle Condition and Fail-safe Operation when Malfunction Detected

Vehicle Condition when Malfunction Detected

Fail-safe Operation when Malfunction Detected

Key registration will be prohibited

-
Related Data List and Active Test

DTC No.

Data List and Active Test

B278D

-

CAUTION / NOTICE / HINT

NOTICE:

  • When using the Techstream with the engine 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, Gasoline Model) 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, Gasoline Model) after confirming that the communication systems are functioning properly.

    Click here

  • Before performing following procedure, check that the ID code box (immobiliser code ECU) is not installed on the vehicle.
  • Before replacing the certification ECU (smart key ECU assembly), refer to Registration.

    Click here

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

PROCEDURE

1.

CLEAR DTC

(a) Clear the DTCs.

Body Electrical > Smart Key > Clear DTCs
NEXT

2.

CHECK DTC OUTPUT

(a) Check for DTCs.

Body Electrical > Smart Key > Trouble Codes

HINT:

Before checking for DTCs, perform the "DTC Output Confirmation Operation" procedure.

OK:

DTC B278D is not output.

OK

END
NG

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

Additional Key cannot be Registered. Open in Front Floor Electrical Key Oscillator Circuit (B27A5). Open in Rear Floor Electrical Key Oscillator Circuit (B27A6)

Engine Immobiliser System Circuit Short to Battery (B279A12). Engine Immobiliser System Incorrect Assembly (B279C95). Ignition Hold Monitor Malfunction (B2271)

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Toyota Avalon (XX50) 2019-2022 Service & Repair Manual

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