AUTOMATIC TRANSMISSION SYSTEM - Pattern Select Switch Power 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.

The ECM memory contains the programs for the NORMAL and POWER shift patterns and lock-up pattern.

By following the programs corresponding to the signals from the pattern select switch, the neutral start and other various sensors, the ECM switches the solenoid valves ON and OFF, and controls the transmission gear change and the lock-up clutch operation.

WIRING DIAGRAM

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

INSPECTION PROCEDURE

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

Disconnect the connector of pattern select switch.

Automatic Transmission System - Pattern Select Switch Power 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 Connection Specified Condition
3 - Body ground Below 1 Ω

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

2.INSPECT PATTERN SELECT SWITCH ASSEMBLY

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

Standard resistance:
Switch Condition Tester Connection Specified Condition
Pattern select switch
(PWR) 3 - 7 Below 1 Ω
Pattern select switch
(NORM) ↑ 10 kΩ or higher

NG

REPLACE PATTERN SELECT SWITCH ASSEMBLY

OK

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

Connect the connector of pattern select switch.

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

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

Standard resistance:
Switch Condition Tester Connection Specified Condition
Pattern select switch
(PWR) J75 - 18 (PWR) - Body ground Below 1 Ω
Pattern select switch
(NORM) ↑ 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

Tester Connection	Specified Condition
3 - Body ground	Below 1 Ω

Switch Condition	Tester Connection	Specified Condition
Pattern select switch (PWR)	3 - 7	Below 1 Ω
Pattern select switch (NORM)	↑	10 kΩ or higher

Switch Condition	Tester Connection	Specified Condition
Pattern select switch (PWR)	J75 - 18 (PWR) - Body ground	Below 1 Ω
Pattern select switch (NORM)	↑	10 kΩ or higher