DTC P1752-31: Fail Safe Signal (Gear Shift Control Module "B" to "A") No Signal [09/2023 - ]: Procedure
WARNING: This page is about a different car, the 2024 Lexus TX 500h. However, it is still accessible from the selected car via links, so may be relevant.
- INSPECT SHIFT ACTUATOR ECU (SHIFT CONTROL ACTUATOR ASSEMBLY) (CHECK FS TERMINAL WAVEFORM)
Pre-procedure1
- Connect an oscilloscope between the shift control ECU (transmission floor shift assembly) terminals specified in the table below.
- Turn the ignition switch to ON.
- Measure the waveform.
*a Component with harness connected
(Shift Control ECU (Transmission Floor Shift Assembly))*b Waveform (Fail Safe Signal) Tester Connection Condition Equipment Setting D25-14 (FS) - D25-9 (E1) Ignition switch ON 10 V/DIV., 20 ms./DIV. HINT:
Perform the inspection with the connector of the shift control ECU and shift actuator ECU connected.
Result
Proceed to OK NG
Post-procedure1
- Turn the ignition switch off.
Result:
OK
REPLACE SHIFT CONTROL ECU (TRANSMISSION FLOOR SHIFT ASSEMBLY). Refer to REMOVAL [09/2023 - ]
Result:
NG
See step 2
- CHECK HARNESS AND CONNECTOR (SHIFT CONTROL ECU - SHIFT ACTUATOR ECU)
Pre-procedure1
- Disconnect the D25 shift control ECU (transmission floor shift assembly) connector.
- Disconnect the C64 shift actuator ECU (shift control actuator assembly) connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition Result D25-14 (FS) - C64-6 (FS) Always Below 1 Ω Ω D25-14 (FS) or C64-6 (FS) - Body ground and other terminals Always 10 kΩ or higher kΩ Result
Proceed to OK NG
Post-procedure1
- Connect the shift actuator ECU (shift control actuator assembly) connector.
- Connect the shift control ECU (transmission floor shift assembly) connector.
Result:
OK
REPLACE SHIFT ACTUATOR ECU (SHIFT CONTROL ACTUATOR ASSEMBLY). Refer to REMOVAL [09/2023 - ]
Result:
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR