Lexus IS250 IS220d GSE20 ALE20 - A960E AUTOMATIC TRANSMISSION

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

DRIVING TEST

CHECK HARNESS AND CONNECTOR (PATTERN SELECT SWITCH ASSEMBLY - BODY GROUND)

INSPECT PATTERN SELECT SWITCH ASSEMBLY

CHECK HARNESS AND CONNECTOR (PATTERN SELECT SWITCH ASSEMBLY - MAIN BODY ECU)

AUTOMATIC TRANSMISSION SYSTEM - Pattern Select Switch Snow Mode Circuit

DESCRIPTION

Cowl side J/B ECU receives pattern select switch information, and sends it through the multiplex communication system and CAN system to the ECM.


ECT SNOW is the system that operates the throttle motor to control engine output to reduce skidding of the driving wheels, guarantee takeoff acceleration, driving straightness and turning stability.


WIRING DIAGRAM

Automatic Transmission System - Pattern Select Switch Snow Mode Circuit. A960E AUTOMATIC TRANSMISSION. Lexus IS250 IS220d GSE20 ALE20

  • HINT:
  • (*) Pattern Select Switch (ECT SNOW Switch)
  • When the ECT SNOW switch is pushed, the switch contact is made and the ECT SNOW mode is selected.
  • To cancel the ECT SNOW mode, push the ECT SNOW switch once again.
  • The ECT SNOW mode is automatically cancelled out when the ignition switch is turned "OFF".

INSPECTION PROCEDURE

1.DRIVING TEST

Start the engine.

Turn the ECT SNOW switch "OFF" (Normal drive mode).

Confirm vehicle response by driving from a parked position to fully depressing the accelerator pedal.

Turn the ECT SNOW switch "ON" and perform the same check as above.


Confirm that there is a difference between ECT SNOW switch "ON" and "OFF".

  • HINT:
Driving test should be done on a paved road (a nonskid road).
Make sure not to use the TRAC system when testing a vehicle equipped with one.
  • OK:
  • There is a difference in acceleration between "ON" and "OFF".
NG
Go to step 2
OK
PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
2.CHECK HARNESS AND CONNECTOR (PATTERN SELECT SWITCH ASSEMBLY - BODY GROUND)

Disconnect the connector of pattern select switch.

Automatic Transmission System - Pattern Select Switch Snow Mode Circuit. A960E AUTOMATIC TRANSMISSION. Lexus IS250 IS220d GSE20 ALE20

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

  • Standard resistance:
  • Tester ConnectionSpecified Condition
    3 - Body groundBelow 1 Ω
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK
3.INSPECT PATTERN SELECT SWITCH ASSEMBLY
Automatic Transmission System - Pattern Select Switch Snow Mode Circuit. A960E AUTOMATIC TRANSMISSION. Lexus IS250 IS220d GSE20 ALE20

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

  • Standard resistance:
  • Switch ConditionTester ConnectionSpecified Condition
    Press continuously Pattern select switch
    (SNOW)    		1 - 3Below 1 Ω
    Release Pattern select switch
    (SNOW)    		↑10 kΩ or higher
NG
REPLACE PATTERN SELECT SWITCH ASSEMBLY
OK
4.CHECK HARNESS AND CONNECTOR (PATTERN SELECT SWITCH ASSEMBLY - MAIN BODY ECU)
Automatic Transmission System - Pattern Select Switch Snow Mode Circuit. A960E AUTOMATIC TRANSMISSION. Lexus IS250 IS220d GSE20 ALE20

Connect the connector of pattern select switch.

Disconnect the cowl side junction block (main body ECU RH) connector.

Measure the resistance between terminal SNOW of the cowl side junction block (main body ECU RH) and body ground.

  • Standard resistance:
  • Switch ConditionTester ConnectionSpecified Condition
    Press continuously Pattern select switch
    (SNOW)    		J75-17 (SNOW) - Body groundBelow 1 Ω
    Release Pattern select switch
    (SNOW)    		↑10 kΩ or higher
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK
PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
LEXUS IS250, IS220d / GSE20 ALE20
A960E AUTOMATIC TRANSMISSION
Lexus IS250 IS220d GSE20 ALE20
AUTOMATIC TRANSMISSION SYSTEM