Toyota Yaris: Smart Key System (for Start Function) / ACC Circuit Short to Ground (B227411)

Toyota Yaris XP210 (2020-2025) Reapir and Service Manual / Vehicle Interior / Theft Deterrent / Keyless Entry / Smart Key System (for Start Function) / ACC Circuit Short to Ground (B227411)

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
B227411	ACC Circuit Short to Ground	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.	Power distribution box assembly Certification ECU (smart key ECU assembly) Wire harness or connector	Wait 10 seconds after turning the ignition switch to ACC or ON, and then wait another 10 seconds after turning the ignition switch off.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Note

B227411

ACC Circuit Short to Ground

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.

Power distribution box assembly
Certification ECU (smart key ECU assembly)
Wire harness or connector

Wait 10 seconds after turning the ignition switch to ACC or ON, and then wait another 10 seconds after turning the ignition 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 ignition 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 ignition switch is ACC. HINT: The ignition switch can be turned to ON 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 ignition 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 ignition switch is ACC.

HINT:

The ignition switch can be turned to ON and the engine can be started.

Related Data List and Active Test Items

DTC No.	Data List and Active Test
B227411	Power Source Control ACC Relay Monitor

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

When using the GTS with the ignition switch off, connect the GTS to the DLC3 and turn a courtesy light switch on and off at intervals of 1.5 seconds or less until communication between the GTS and the vehicle begins. Then select the vehicle type under manual mode and enter the following menus: Body Electrical / Smart Key. While using the GTS, periodically turn a courtesy light switch on and off at intervals of 1.5 seconds or less to maintain communication between the GTS 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 for circuits related to this system before performing the following procedure.
Before replacing the certification ECU (smart key ECU assembly), refer to Registration.
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After repair, confirm that no DTCs are output by performing "DTC Output Confirmation Operation".

PROCEDURE

1.	CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - POWER DISTRIBUTION BOX ASSEMBLY - BODY GROUND)

(a) Disconnect the H46 certification ECU (smart key ECU assembly) connector.

(b) Disconnect the 4B power distribution box assembly connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
H46-21 (ACCD) - 4B-39	Always	Below 1 Ω
4B-36 - Body ground	Always	Below 1 Ω
H46-21 (ACCD) or 4B-39 - Other terminals and body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

2.	CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
H46-21 (ACCD) - Body ground	Ignition switch off	1 V or less
H46-21 (ACCD) - Body ground	Ignition switch ACC	8.5 V or higher

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

REPLACE POWER DISTRIBUTION BOX ASSEMBLY

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

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