Automatic Transmission System - Transmission Control Switch Circuit
Lexus IS250 IS220d GSE20 ALE20 - A960E AUTOMATIC TRANSMISSION
DESCRIPTION
WIRING DIAGRAM
INSPECTION PROCEDURE
CHECK HARNESS AND CONNECTOR (BATTERY - TRANSMISSION CONTROL SWITCH)
CHECK HARNESS AND CONNECTOR (TRANSMISSION CONTROL SWITCH - BODY GROUND)
INSPECT TRANSMISSION CONTROL SWITCH
CHECK HARNESS AND CONNECTOR (TRANSMISSION CONTROL SWITCH - ECM)
AUTOMATIC TRANSMISSION SYSTEM - Transmission Control Switch Circuit
DESCRIPTION
When moving the shift lever into the S position using the transmission control switch, it is possible to switch the shift range position between "1" (first range) and "6" (sixth range).
Shifting up "+" once raises one shift range position, and shifting down "-" lowers one shift range position.
WIRING DIAGRAM
INSPECTION PROCEDURE
| 1.CHECK HARNESS AND CONNECTOR (BATTERY - TRANSMISSION CONTROL SWITCH) |
Disconnect the transmission control switch connector of shift lock control unit assembly.
Measure the voltage according to the value(s) in the table below.
- Standard voltage:
| Switch Condition | Tester Connection | Specified Condition |
| Engine switch on (IG) | 3 - Body ground | 10 to 14 V |
| Engine switch off | ↑ | Below 1 V |
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
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| 2.CHECK HARNESS AND CONNECTOR (TRANSMISSION CONTROL SWITCH - BODY GROUND) |
Measure the resistance according to the value(s) in the table below.
- Standard resistance:
| Tester Connection | Specified Condition |
| 5 - Body ground | Below 1 Ω |
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|
| 3.INSPECT TRANSMISSION CONTROL SWITCH |
Measure resistance between each terminal of shift lock control unit assembly when the shift lever is moved to each position.
- Standard resistance:
| Shift Position | Tester Connection | Specified Condition |
| S, "+" and "-" | 3 - 7 | Below 1 Ω |
| Except S, "+" and "-" | ↑ | 10 kΩ or higher |
Press continuously
"+"
(Up shift) | 2 - 5 | Below 1 Ω |
| S | ↑ | 10 kΩ or higher |
Press continuously
"-"
(Down shift) | 1 - 5 | Below 1 Ω |
| S | ↑ | 10 kΩ or higher |
| | REPLACE TRANSMISSION CONTROL SWITCH |
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| 4.CHECK HARNESS AND CONNECTOR (TRANSMISSION CONTROL SWITCH - ECM) |
Connect the transmission control switch connector of shift lock control unit assembly.
Disconnect the ECM connector.
Turn the ignition switch on (IG) position, and measure the voltage according to the value(s) in the table below when the shift lever is moved to each position.
- Standard voltage:
| Shift Position | Tester Connection | Specified Condition |
| S, "+" and "-" | A6-9 (S) - Body ground | 10 to 14 V |
| Except S, "+" and "-" | ↑ | Below 1 V |
Turn the ignition switch off position.
Disconnect the ECM connector.
Measure the resistance according to the value(s) in the table below when the shift lever is moved to each position.
- Standard resistance:
| Shift Position | Tester Connection | Specified Condition |
Press continuously
"+"
(Up shift) | A6-30 (SFTU) - Body ground | Below 1 Ω |
| S | ↑ | 10 kΩ or higher |
Press continuously
"-"
(Down shift) | A6-19 (SFTD) - Body ground | Below 1 Ω |
| S | ↑ | 10 kΩ or higher |
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
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| OK | |
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| PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE |
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