Toyota Tacoma 2015-2018 Service Manual: IG2 Signal Malfunction (B2788)

Toyota Tacoma 2015-2018 Service Manual / Steering Column / Steering Lock System / IG2 Signal Malfunction (B2788)

DESCRIPTION

This DTC is stored when the steering lock ECU (steering lock actuator or UPR bracket assembly) detects an IG2 power supply malfunction.

HINT:

The steering lock ECU (steering lock actuator or UPR bracket assembly) is not connected to the CAN communication system. However, the steering lock ECU (steering lock actuator or UPR bracket assembly) is connected to the certification ECU (smart key ECU assembly) via LIN communication and communicates with other components via CAN communication through the certification ECU (smart key ECU assembly).

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	Note
B2788	IG2 Signal Malfunction	Mismatch between the steering lock ECU (steering lock actuator or UPR bracket assembly) IG2 input from the LIN communication system and from the direct line (1-trip detection logic*).	IG2 fuse Steering lock ECU (Steering lock actuator or UPR bracket assembly) Harness or connector	DTC Output Confirmation Operation: No confirmation operation is necessary (monitoring is continuous).

*: Only output while a malfunction is present and the engine 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 steering cannot be locked or unlocked. For this reason, the engine cannot be started.	-

Related Data List and Active Test Items

DTC No.	Data List Item	Active Test Item
B2788	-	-

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

When using the Techstream with the engine switch off, connect the Techstream to the vehicle 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 steering lock system uses LIN communication. First perform the inspections in "How to Proceed with Troubleshooting" to confirm that there are no communication malfunctions before proceeding with troubleshooting (See page ).
Inspect the fuses for circuits related to this system before performing the following procedure.
After performing repairs, confirm that no DTCs are output again (See page ).
When replacing the steering lock ECU (steering lock actuator or UPR bracket assembly), registration must be performed (See page ).

PROCEDURE

1.	INSPECT STEERING LOCK ECU (STEERING LOCK ACTUATOR OR UPR BRACKET ASSEMBLY) (POWER SOURCE MODE SIGNAL)

(a) Make sure that there is no looseness at the locking part and the connecting part of the connector.

(b) Disconnect the steering lock ECU (steering lock actuator or UPR bracket assembly) connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
S45-1 (GND) - Body ground	Always	Below 1 Ω

Text in Illustration

*a	Front view of wire harness connector (to Steering Lock ECU (Steering Lock Actuator or UPR Bracket Assembly))

(d) Reconnect the steering lock ECU (steering lock actuator or UPR bracket assembly) connector.

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
S45-6 (IG2) - S45-1 (GND)	Engine switch on (IG)	11 to 14 V
S45-6 (IG2) - S45-1 (GND)	Engine switch off	Below 1 V

Text in Illustration

*a	Component with harness connected (Steering Lock ECU (Steering Lock Actuator or UPR Bracket Assembly))

REPLACE STEERING LOCK ECU (STEERING LOCK ACTUATOR OR UPR BRACKET ASSEMBLY)

REPAIR OR REPLACE HARNESS OR CONNECTOR

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