DTC P177A-87: Lost Communication with Gear Shift Control Module Backup Power Supply Missing Message [09/2023 - ]: Procedure
- CHECK HARNESS AND CONNECTOR (SHIFT CONTROL ECU - INTEGRATED CAPACITOR)
Pre-procedure1
- Disconnect the D25 shift control ECU (transmission floor shift assembly) connector.
- Disconnect the J14 integrated capacitor (integration control supply) connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition Result D25-17 (BUBI) - J14-15 (RO) Always Below 1 Ω Ω D25-17 (BUBI) or J14-15 (RO) - Body ground and other terminals Always 10 kΩ or higher kΩ Result
Proceed to OK NG
Post-procedure1
- Connect the integrated capacitor (integration control supply) connector.
- Connect the shift control ECU (transmission floor shift assembly) connector.
Result:
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
Result:
OK
See step 2
- INSPECT SHIFT CONTROL ECU (TRANSMISSION FLOOR SHIFT ASSEMBLY) (CHECK BUBI 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 (Integrated capacitor condition signal) Tester Connection Condition Equipment Setting D25-17 (BUBI) - D25-9 (E1) Ignition switch ON 10 V/DIV., 10 ms./DIV. HINT:
The duty ratio changes according to the vehicle condition.
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 3
- INSPECT INTEGRATED CAPACITOR (+B TERMINAL VOLTAGE)
Pre-procedure1
- Disconnect the J14 integrated capacitor (integration control supply) connector.
- Measure the voltage according to the value(s) in the table below.
Standard Voltage
Tester Connection Condition Specified Condition Result J14-7 (+B) - Body ground Always 11 to 14 V V Result
Proceed to OK NG
Post-procedure1
- Connect the integrated capacitor (integration control supply) connector.
Result:
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
Result:
OK
See step 4
- INSPECT INTEGRATED CAPACITOR (IG TERMINAL VOLTAGE)
Pre-procedure1
- Disconnect the J14 integrated capacitor (integration control supply) connector.
- Turn the ignition switch to ON.
- Measure the voltage according to the value(s) in the table below.
Standard Voltage
Tester Connection Condition Specified Condition Result J14-16 (IG) - Body ground Ignition switch ON 11 to 14 V V Result
Proceed to OK NG NOTE:Turning the ignition switch to ON with the connector disconnected causes other DTCs to be stored. Clear the DTCs after performing this inspection.
Post-procedure1
- Turn the ignition switch off.
- Connect the integrated capacitor (integration control supply) connector.
Result:
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
Result:
OK
See step 5
- CHECK HARNESS AND CONNECTOR (SHIFT CONTROL ECU - INTEGRATED CAPACITOR)
Pre-procedure1
- Disconnect the D25 shift control ECU (transmission floor shift assembly) connector.
- Disconnect the J14 integrated capacitor (integration control supply) connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition Result D25-13 (BUB) - J14-6 (BUSE) Always Below 1 Ω Ω D25-13 (BUB) or J14-6 (BUSE) - Body ground and other terminals Always 10 kΩ or higher kΩ Result
Proceed to OK NG
Post-procedure1
- Connect the integrated capacitor (integration control supply) connector.
- Connect the shift control ECU (transmission floor shift assembly) connector.
Result:
OK
REPLACE INTEGRATED CAPACITOR (INTEGRATION CONTROL SUPPLY). Refer to REMOVAL [09/2023 - 12/2023] , or refer to REMOVAL [12/2023 - ]
Result:
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR