Dtc B2788 Ig2 Signal Malfunction

Steering. Lexus Is250, Is220D. Gse20 Ale20
Steering Column. Lexus Is250, Is220D. Gse20 Ale20

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

INSPECT IG2 RELAY

CHECK HARNESS AND CONNECTOR (STEERING LOCK ACTUATOR ASSEMBLY - BODY GROUND)

CHECK HARNESS AND CONNECTOR (STEERING LOCK ACTUATOR ASSEMBLY - BATTERY)

DTC B2788 IG2 Signal Malfunction


DESCRIPTION

The steering lock ECU receives power from the IG2 relay. When the voltage value indicated by the IG signal from the certification ECU equals to the voltage that is applied to the steering lock ECU, the steering will be unlocked. The steering lock ECU will not lock the steering when power from the IG2 relay is present (this prevents the steering from being locked while the vehicle is moving).

DTC No.
DTC Detecting Condition
Trouble Area
B2788
Different information is obtained from IG2 signals received directly from the IG2 circuit, and from IG2 signals sent via LIN communication for a period of 1 second.
  1. IG2 relay
  2. Wire harness
  3. Power source control ECU
  4. Steering lock actuator assembly (Steering lock ECU)

WIRING DIAGRAM


Lexus Is250, Is220D. Gse20 Ale20.Steering Column.Steering System. Dtc B2788 Ig2 Signal Malfunction


INSPECTION PROCEDURE

1.INSPECT IG2 RELAY


    Lexus Is250, Is220D. Gse20 Ale20.Steering Column.Steering System. Dtc B2788 Ig2 Signal Malfunction

  1. Remove the IG2 relay from the engine room R/B No.2.

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

    Standard resistance:
    Tester Connection
    		Specified Condition
    3 - 5
    		10 kΩ or higher
    3 - 5
    		Below 1 Ω
    (when battery voltage is applied to terminals 1 and 2)


NG
REPLACE IG2 RELAY
OK


2.CHECK HARNESS AND CONNECTOR (STEERING LOCK ACTUATOR ASSEMBLY - BODY GROUND)


    Lexus Is250, Is220D. Gse20 Ale20.Steering Column.Steering System. Dtc B2788 Ig2 Signal Malfunction

  1. Disconnect the J29 connector from the steering lock actuator assembly.

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

    Standard resistance:
    Tester connection
    (Symbols)
    		Condition
    		Specified condition
    J29-1 (GND) - Body ground
    		Always
    		Below 1 Ω
    J29-2 (SGND) - Body ground
    		Always
    		Below 1 Ω


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


3.CHECK HARNESS AND CONNECTOR (STEERING LOCK ACTUATOR ASSEMBLY - BATTERY)


    Lexus Is250, Is220D. Gse20 Ale20.Steering Column.Steering System. Dtc B2788 Ig2 Signal Malfunction

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

    Standard voltage:
    Tester connection
    (Symbols)
    		Condition
    		Specified condition
    J29-6 (IG2) - J29-1 (GND)
    		Engine switch on (IG)
    		10 to 14 V
    J29-6 (IG2) - J29-2 (SGND)
    		Engine switch on (IG)
    		10 to 14 V

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

    Standard resistance:
    Tester connection
    (Symbols)
    		Condition
    		Specified condition
    *J29-6 (IG2) - J29-7 (B)
    		Engine switch off
    		10 kΩ or higher
    *: This measurement is performed with the engine switch off to check for a battery voltage short in the IG2 circuit.


OK
REPLACE STEERING LOCK ACTUATOR ASSEMBLY (STEERING LOCK ECU)
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (STEERING LOCK ACTUATOR ASSEMBLY - BATTERY)