Toyota Avalon (XX50): ACC Monitor Malfunction (B2274). STSW Monitor Malfunction (B2275). Detecting Vehicle Submersion (B2277)

Toyota Avalon (XX50) 2019-2022 Service & Repair Manual / Vehicle Interior / Theft Deterrent / Keyless Entry / Smart Key System(for Start Function, Hv Model) / ACC Monitor Malfunction (B2274). STSW Monitor Malfunction (B2275). Detecting Vehicle Submersion (B2277)

ACC Monitor Malfunction (B2274)

DESCRIPTION

This DTC is stored when a malfunction in the ACC output circuit is detected. The ACC output circuit is the circuit between terminal ACCD of the certification ECU (smart key ECU assembly) and the ACC relay.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	Note
B2274	ACC Monitor Malfunction	The ACC relay circuit of the certification ECU (smart key ECU assembly) is malfunctioning. (1-trip detection logic*) HINT: When the voltage at terminal ACCD is not at the standard, the system is determined to be malfunctioning.	Instrument panel junction block assembly Certification ECU (smart key ECU assembly) Wire harness or connector	Wait 10 seconds after turning the power switch on (ACC) or on (IG), and then wait another 10 seconds after turning the power switch off.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Note

B2274

ACC Monitor Malfunction

The ACC relay circuit of the certification ECU (smart key ECU assembly) is malfunctioning. (1-trip detection logic*)

HINT:

When the voltage at terminal ACCD is not at the standard, the system is determined to be malfunctioning.

Instrument panel junction block assembly
Certification ECU (smart key ECU assembly)
Wire harness or connector

Wait 10 seconds after turning the power switch on (ACC) or on (IG), and then wait another 10 seconds after turning the power switch off.

*: 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
If there is a malfunction due to the ACC relay being stuck on, the ACC relay does not turn off even though the power switch is off. If there is a malfunction due to the ACC relay being stuck off, the ACC relay does not turn on even though the power switch is on (ACC). HINT: The power switch can be turned on (IG) and the hybrid control system can be started.	-

Vehicle Condition when Malfunction Detected

Fail-safe Function when Malfunction Detected

If there is a malfunction due to the ACC relay being stuck on, the ACC relay does not turn off even though the power switch is off.
If there is a malfunction due to the ACC relay being stuck off, the ACC relay does not turn on even though the power switch is on (ACC).

HINT:

The power switch can be turned on (IG) and the hybrid control system can be started.

Related Data List and Active Test Items

DTC No.	Data List and Active Test
B2274	Power Source Control ACC Relay Monitor

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, HV 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, HV 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.
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.	CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - CERTIFICATION ECU (SMART KEY ECU ASSEMBLY), AUXILIARY BATTERY AND BODY GROUND)

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

(b) Disconnect the 4A, 4D and 4K instrument panel junction block assembly connectors.

Standard Resistance:

Tester Connection	Condition	Specified Condition
G40-16 (ACCD) - 4A-30	Always	Below 1 Ω
4D-3 - Body ground	Always	Below 1 Ω
G40-16 (ACCD) or 4A-30 - Other terminals and body ground	Always	10 kΩ or higher

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
4K-1 - Body ground	Power switch off	11 to 14 V

REPAIR OR REPLACE HARNESS OR CONNECTOR

2.	CHECK INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY (ACC RELAY)

(a) Remove the instrument panel junction block assembly.

Click here

(b) Connect all of the instrument panel junction block assembly connectors.

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

Component with harness connected

(Instrument Panel Junction Block Assembly)

Standard Voltage:

Tester Connection	Condition	Specified Condition
4H-26 - Body ground	Power switch on (ACC)	11 to 14 V

REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

3.	CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
G40-16 (ACCD) - Body ground	Power switch off → Power switch on (ACC)	1 V or less → 8.5 V or higher

*a	Component with harness connected (Certification ECU (Smart Key ECU Assembly))

END (TEMPORARY CONNECTION FAILURE IS SUSPECTED)

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

STSW Monitor Malfunction (B2275)

DESCRIPTION

This DTC is stored when a malfunction is detected in the starter circuit inside the certification ECU (smart key ECU assembly).

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	Note
B2275	STSW Monitor Malfunction	Certification ECU (smart key ECU assembly) internal HV activation request output circuit malfunction or external circuit malfunction (1-trip detection logic*)	Certification ECU (smart key ECU assembly) Hybrid vehicle control ECU Wire harness or connector	Turn the power switch on (IG) and wait 10 seconds or more, then start the hybrid control system 3 times.

*: Only detected while a malfunction is present and the power switch is on (IG).

Vehicle Condition and Fail-safe Function when Malfunction Detected

Vehicle Condition when Malfunction Detected	Fail-safe Function when Malfunction Detected
The power source mode changes to on (READY) even though the hybrid control system is not started. The power source mode does not change to on (READY) even though the hybrid control system is started.	-

Related Data List and Active Test Items

DTC No.	Data List and Active Test
B2275	Power Source Control Starter Request Signal

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, HV 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, HV Model) after confirming that the communication systems are functioning properly.
Click here
Before replacing the hybrid vehicle control ECU or 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.	CHECK FOR DTC

(a) Turn the power switch on (IG) and wait 25 seconds.

(b) Using the Techstream, check for certification ECU (smart key ECU assembly) DTCs.

Body Electrical > Power Source Control > Trouble Codes

OK:

DTC B2285 is not output simultaneously.

GO TO DTC B2285

2.	CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - HYBRID VEHICLE CONTROL ECU)

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

(b) Disconnect the G46 hybrid vehicle control ECU connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
G40-27 (ST2) - G46-9 (ST2)	Always	Below 1 Ω
G40-27 (ST2) or G46-9 (ST2) - Other terminals and body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

3.	CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

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

(b) Reconnect the G46 hybrid vehicle control ECU connector.

Standard Voltage:

Tester Connection	Condition	Specified Condition
G40-27 (ST2) - Body ground	With the brake pedal depressed, the power switch is pressed and held → After approx. 3 sec. has elapsed, the power switch is released	8.5 V or higher → 1 V or less

REPLACE HYBRID VEHICLE CONTROL ECU

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

Detecting Vehicle Submersion (B2277)

DESCRIPTION

This DTC is stored when a malfunction in the water submersion detection circuit inside the certification ECU (smart key ECU assembly) is detected.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	Note
B2277	Detecting Vehicle Submersion	Water submersion detected by the water submersion detection circuit inside the certification ECU (smart key ECU assembly). (1-trip detection logic*)	Certification ECU (smart key ECU assembly)	Wait 300 seconds after connecting the cable to the negative (-) auxiliary battery terminal.

*: 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 power switch cannot be turned off and the hybrid control system cannot be started.	-

Related Data List and Active Test Items

DTC No.	Data List and Active Test
B2277	-

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

HINT:

Before proceeding with troubleshooting, check if there are any signs of water damage to the certification ECU (smart key ECU assembly). If there are any signs of water damage, replace the certification ECU (smart key ECU assembly) and take measures against the cause of the water damage.

PROCEDURE

1.	CHECK WATER INTRUSION

(a) Check that the certification ECU (smart key ECU assembly), its ground area and wire harnesses have no signs of water intrusion.

Result	Proceed to
No sign of water intrusion found	A
Signs of water intrusion found	B

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

TAKE MEASURES AGAINST WATER INTRUSION AND REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

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

Engine/Power Switch Malfunction (B2278). Vehicle Speed Signal Malfunction (B2282,B2283). Brake Signal Malfunction (B2284)

See More:

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