Toyota CH-R Service Manual: ACC Monitor Malfunction (B2274)

Toyota CH-R Service Manual / Theft Deterrent / Keyless Entry / 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 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.	AM2 fuse Instrument panel junction block assembly 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 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.

AM2 fuse
Instrument panel junction block assembly
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 ACC 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 ACC 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 ACC 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 ACC 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.

Related Data List and Active Test Items

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

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 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.
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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 smart key system (for Start Function) Precaution.
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After repair, confirm that no DTCs are output by performing "DTC Output Confirmation Operation".

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.

PROCEDURE

1.	CHECK HARNESS AND CONNECTOR (POWER SOURCE)

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

2.	CHECK HARNESS AND CONNECTOR (GROUND)

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REPAIR OR REPLACE HARNESS OR CONNECTOR

3.	CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)

(a) Disconnect the F1 certification ECU (smart key ECU assembly) connector.

(b) Disconnect the 3A and 3D instrument panel junction block assembly connectors.

Standard Resistance:

Tester Connection	Condition	Specified Condition
F1-16 (ACCD) - 3A-30	Always	Below 1 Ω
3D-3 - Body ground	Always	Below 1 Ω
F1-16 (ACCD) or 3A-30 - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

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

(a) Remove the instrument panel junction block assembly.

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

Component without harness connected

(Instrument Panel Junction Block Assembly)

Standard Resistance:

Tester Connection	Condition	Specified Condition
3A-30 - 3D-3	20°C (68°F)	285.71 to 428.57 Ω
3K-1 - 3A-40	Battery voltage not applied between terminals 3A-30 and 3D-3	10 kΩ or higher
3K-1 - 3A-40	Battery voltage not applied between terminals 3A-30 and 3D-3	Below 1 Ω

REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

5.	CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

(a) Reconnect the F1 certification ECU (smart key ECU assembly) connector.

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

(b) Install the instrument panel junction block assembly.

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Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
F1-16 (ACCD) - Body ground	Engine switch off → Engine switch on (ACC)	1 V or less → 8.5 V or higher

END (TEMPORARY CONNECTION FAILURE IS SUSPECTED)

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

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