Transmission Control Switch Circuit [11/2021 - ]: Procedure
WARNING: This page is about a different car, the 2024 Lexus IS 500, 2023 Lexus IS 500, and 2022 Lexus IS 500. However, it is still accessible from the selected car via links, so may be relevant.
- INSPECT TRANSMISSION CONTROL SWITCH (TRANSMISSION FLOOR SHIFT ASSEMBLY)
- Disconnect the K80 transmission floor shift assembly (transmission control switch) connector.
*a Component without harness connected
(Transmission Floor Shift Assembly (Transmission Control Switch)) - Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition 4 (IG) - 5 (S) Shift lever in M, "+" and "-" Below 1 Ω Shift lever not in M, "+" and "-" 10 kΩ or higher 3 (SFTU) - 2 (E) Shift lever held in "+" (Up shift) Below 1 Ω Shift lever in M 10 kΩ or higher 1 (SFTD) - 2 (E) Shift lever held in "-" (Down shift) Below 1 Ω Shift lever in M 10 kΩ or higher Result
Proceed to OK NG
Result:
NG
REPLACE TRANSMISSION FLOOR SHIFT ASSEMBLY (TRANSMISSION CONTROL SWITCH). Refer to COMPONENTS [11/2021 - ]
Result:
OK
See step 2
- Disconnect the K80 transmission floor shift assembly (transmission control switch) connector.
- CHECK HARNESS AND CONNECTOR (TRANSMISSION CONTROL SWITCH - BATTERY, BODY GROUND)
- Turn the engine switch on (IG).
- Measure the voltage according to the value(s) in the table below.
*a Front view of wire harness connector
(to Transmission Floor Shift Assembly (Transmission Control Switch))Standard Voltage
Tester Connection Condition Specified Condition K80-4 (IG) - Body ground Engine switch on (IG) 11 to 14 V Engine switch off Below 1 V - Turn the engine switch off.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition K80-2 (E) - Body ground Always Below 1 Ω Result
Proceed to OK NG
Result:
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (TRANSMISSION CONTROL SWITCH - BATTERY, BODY GROUND)
Result:
OK
See step 3
- CHECK HARNESS AND CONNECTOR (TRANSMISSION CONTROL SWITCH - ECM)
- Connect the K80 transmission floor shift assembly (transmission control switch) connector.
- Disconnect the A117 ECM connector.
*a Rear view of wire harness connector
(to ECM) - Turn the engine switch on (IG).
- Measure the voltage according to the value(s) in the table below.
Standard Voltage
Tester Connection Condition Specified Condition A117-6 (S) - Body ground Shift lever in M, "+" and "-" 11 to 14 V Shift lever not in M, "+" and "-" Below 1 V - Turn the engine switch off.
- Disconnect the spiral cable with sensor sub-assembly connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition A117-29 (SFTU) - Body ground Shift lever held in "+" (Up shift) Below 1 Ω Shift lever in M 10 kΩ or higher A117-28 (SFTD) - Body ground Shift lever held in "-" (Down shift) Below 1 Ω Shift lever in M 10 kΩ or higher Result
Proceed to OK NG
Result:
OK
PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to PROBLEM SYMPTOMS TABLE [11/2021 - ]
Result:
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (TRANSMISSION CONTROL SWITCH - ECM)