Toyota Tacoma (2015-2018) Service Manual: Ignition Hold Monitor Malfunction (B2271)

Toyota Tacoma (2015-2018) Service Manual / 2gr-fks Starting / Smart Key System(for Start Function) / Ignition Hold Monitor Malfunction (B2271)

DESCRIPTION

This DTC is stored when a malfunction in the IG circuit or IG hold circuit in the certification ECU (smart key ECU assembly) is detected.

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
B2271	When either of the following conditions is met (1-trip detection logic*): The IG circuit in the certification ECU (smart key ECU assembly) is malfunctioning. The IG hold circuit in the certification ECU (smart key ECU assembly) is malfunctioning.	AM2 NO. 2 fuse Certification ECU (smart key ECU assembly) Wire harness or connector	IG ON

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

HINT:

The IG circuits activate the IG relays.
After the IG circuits turn on, even if the CPU operates incorrectly, the IG hold circuit maintains the power source mode in on (IG).

Vehicle Condition and Fail-safe Function when Malfunction Detected

Vehicle Condition when Malfunction Detected	Fail-safe Function when Malfunction Detected
The engine switch cannot be turned on (IG) (the engine cannot be started).	The power source mode cannot be changed to on (IG).

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
B2271	Power Source Control IG Relay Monitor (Inside) Latch Circuit Starting Control Ignition	-

PROCEDURE

1.	CHECK HARNESS AND CONNECTOR (POWER SOURCE)

(a) Disconnect 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
C29-10 (+B) - Body ground	Always	11 to 14 V

Text in Illustration

*a	Rear view of wire harness connector (to Certification ECU (smart key ECU assembly))

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

2.	CHECK HARNESS AND CONNECTOR (GROUND)

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

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
C29-11 (E) - Body ground	Always	Below 1 Ω

Text in Illustration

*a	Front view of wire harness connector (to Certification ECU (smart key ECU assembly))

REPAIR OR REPLACE HARNESS OR CONNECTOR

3.	CHECK 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
C27-3 (IG1D) - Body ground	Engine switch on (ACC) → Engine switch on (IG)	1 V or less → 9 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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