DTC P176A-87: Lost Communication with Fail Safe Signal (Gear Shift Control Module "A") Missing Message [12/2017 - 10/2023]: Procedure
- CHECK SHIFT CONTROL ECU (CHECK SBFS TERMINAL WAVEFORM)
- Disconnect the A95 ECM connector.
*a Front view of wire harness connector
(to ECM)*b Waveform (Fail-safe signal) - Connect an oscilloscope between the ECM connector terminal specified in the table below and body ground.
- Turn the engine switch on (IG) and measure the waveform.
Tester Connection Condition Equipment Setting A95-15 (SBFS) - Body ground Engine switch on (IG) 10 V/DIV., 20 ms./DIV. NOTE:Turning the engine switch on (IG) with the connector disconnected causes other DTCs to be stored. Clear the DTCs after performing this inspection.
HINT:
The waveforms differ when the shift control ECU is malfunctioning.
- Turn the engine switch off.
- Reconnect the A95 ECM connector.
Result
Proceed to OK NG
Result:
OK
REPLACE ECM. Refer to REMOVAL [12/2017 - 09/2018] , or refer to REMOVAL [09/2018 - 10/2020] , or refer to REMOVAL [10/2020 - 10/2022] , or refer to REMOVAL [10/2022 - 10/2023]
Result:
NG
See step 2
- Disconnect the A95 ECM connector.
- CHECK HARNESS AND CONNECTOR (SHIFT CONTROL ECU - ECM)
- Disconnect the G81 shift control ECU connector.
- Disconnect the A95 ECM connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance (Check for Open)
Tester Connection Condition Specified Condition G81-3 (SBFS) - A95-15 (SBFS) Always Below 1 Ω Standard Resistance (Check for Short)
Tester Connection Condition Specified Condition G81-3 (SBFS) or A95-15 (SBFS) - Body ground and other terminals Always 10 kΩ or higher - Reconnect the A95 ECM connector.
- Reconnect the G81 shift control ECU connector.
Result
Proceed to OK NG
Result:
OK
REPLACE SHIFT CONTROL ECU. Refer to REMOVAL [12/2017 - 09/2018] , or refer to REMOVAL [09/2018 - 10/2020] , or refer to REMOVAL [10/2020 - 10/2022] , or refer to REMOVAL [10/2022 - 10/2023]
Result:
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR