Toyota Tacoma (2015-2018) Service Manual: ACC Monitor Malfunction (B2274)

Toyota Tacoma (2015-2018) Service Manual / 2gr-fks Starting / Smart Key System(for Start Function) / 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 that goes from the ACC output terminal of the certification ECU (smart key ECU assembly) to the ACC relay.

HINT:

When the cable is disconnected and reconnected to the negative (-) battery terminal, the power source mode returns to the state it was in before the cable was disconnected.

DTC Code	DTC Detection Condition	Trouble Area	DTC Output Confirmation Operation
B2274	Malfunction in the ACC relay circuit in the certification ECU (smart key ECU assembly) or in the external circuit (1-trip detection logic*). HINT: When the voltage at terminal ACCD is not at the standard, the system is determined to be malfunctioning.	AM2 NO. 2 fuse Driver side junction block Certification ECU (smart key ECU assembly) Wire harness or connector	Wait 10 seconds after turning the engine switch on (ACC) or on (IG), and then wait another 10 seconds after turning the engine switch off.

DTC Code

DTC Detection Condition

Trouble Area

DTC Output Confirmation Operation

B2274

Malfunction in the ACC relay circuit in the certification ECU (smart key ECU assembly) or in the external circuit (1-trip detection logic*).

HINT:

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

AM2 NO. 2 fuse
Driver side junction block
Certification ECU (smart key ECU assembly)
Wire harness or connector

Wait 10 seconds after turning the engine switch on (ACC) or on (IG), and then wait another 10 seconds after turning the engine 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 relay being stuck on, the ACC relay does not turn off even though the engine switch is off. If there is a malfunction due to the relay being stuck off, the ACC relay does not turn on even though the engine switch is on (ACC). HINT: The engine switch can be turned on (IG) and the engine can be started.	-

Vehicle Condition when Malfunction Detected

Fail-safe Function when Malfunction Detected

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

HINT:

The engine switch can be turned on (IG) and the engine can be started.

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) uses a multiplex communication system (LIN communication system) and the CAN communication system. Inspect the communication function by following How to Proceed with Troubleshooting.
Click here

Troubleshoot the smart key system (for Start Function) after confirming that the communication systems are functioning properly.
Before replacing the certification ECU (smart key ECU assembly), refer to the smart key system (for Start Function) precaution (See page ).
Inspect the fuses of circuits related to this system before performing the following inspection procedure.
After performing repairs, perform the operation that fulfills the DTC output confirmation operation, and then confirm that no DTCs are output again.

Related Data List and Active Test Items

DTC	Data List Item	Active Test Item
B2274	Power Source Control ACC Relay Monitor Starting Control Ignition	-

PROCEDURE

1.	CHECK HARNESS AND CONNECTOR (POWER SOURCE)

REPAIR OR REPLACE HARNESS ORCONNECTOR IN CIRCUIT CONNECTED TOPOWER SOURCE

2.	CHECK HARNESS AND CONNECTOR (GROUND)

REPAIR OR REPLACE HARNESS OR CONNECTOR

3.	CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECUASSEMBLY) - DRIVER SIDE JUNCTION BLOCK)

(a) Disconnect the C29 connector from the certification ECU (smart key ECU assembly).

(b) Disconnect the connector from the driver side junction block.

Standard Resistance:

Tester Connection	Condition	Specified Condition
C29-9 (ACCD) - 1A-28	Always	Below 1 Ω
1D-5 - Body ground	Always	Below 1 Ω
C29-9 (ACCD) or 1A-28 - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

4.	CHECK DRIVER SIDE JUNCTION BLOCK (ACC RELAY)

(a) Remove the driver side junction block. (See page Text in Illustration )

Text in Illustration

Component without harness connected

(Driver Side Junction Block)

(b) Remove the main body ECU (multiplex network body ECU) from the driver side junction block. (See page (c) Measure the resistance according to the value(s) in the table below. )

Standard Resistance:

Tester Connection	Condition	Specified Condition
1K-1 - 1F-24	Battery voltage not applied to terminals 1A - 28 and 1D-5	10 kΩ or higher
1K-1 - 1F-24	Battery voltage applied to terminals 1A - 28 and 1D-5	Below 1 Ω

REPLACE DRIVER SIDE JUNCTION BLOCK

5.	INSPECT CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

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

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
C29-9 (ACCD) - Body ground	Engine switch off → Engine switch on (ACC)	1 V or less → 8.5 V or higher

Text in Illustration

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

USE SIMULATION METHOD TO CHECK

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

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