DTC U1176-87: Lost Communication with Gear Shift Control Module "A" (ch2) Missing Message [10/2022 - ]: Procedure

Pre-procedure1

• Turn the ignition switch to ON.

• Check for DTCs.

  Powertrain > Transmission > Trouble Codes 

  Result

  Result	Proceed to
  P1779-96 is output	A
  P1779-96 is not output	B

Post-procedure1

• Turn the ignition switch off.

Result: 

A 

GO TO DTC CHART (P1779-96). Refer to  DTC P1779-96: Gear Shift Control Module Backup Power Supply Component Internal Failure [10/2022 - 08/2023]  Refer to  DTC P1779-96: Gear Shift Control Module Backup Power Supply Component Internal Failure [08/2023 - ] 

Result: 

B 

See step  2

Pre-procedure1

• Enter the following menus: Health Check.

• Check for DTCs.

  Result

  Result	Proceed to
  Only U1176-87 is output.	A
  DTCs other than U1176-87 are not output	B

Post-procedure1

• Turn the engine switch off.

Result: 

B 

GO TO DTC CHART. Refer to  DIAGNOSTIC TROUBLE CODE CHART [10/2022 - 08/2023]  , or refer to  DIAGNOSTIC TROUBLE CODE CHART [08/2023 - 10/2024]  , or refer to  DIAGNOSTIC TROUBLE CODE CHART [10/2024 - ] 

Result: 

A 

See step  3

1. Measure the voltage according to the value(s) in the table below.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Component with harness connected (Transmission Floor Shift Assembly (Shift Control ECU))

   Standard Voltage

   Tester Connection	Switch Condition	Specified Condition	Result
   C35-2 (BATT) - C35-9 (E1)	Ignition switch off	11 to 14 V	V

   HINT: 

   As there might be an intermittent malfunction in the transmission floor shift assembly (shift control ECU) power source circuit, inspect the following even if the measured voltage is as specified:

   • Installation condition of fuse(s) (before removing fuse(s)) (BATT circuit)
   • Fuse condition (before and after removing fuse(s)) (BATT circuit)
   • Connection condition of connectors (BATT circuit)
   • Wire harness condition (BATT circuit)
   • Wire harness condition (GND circuit)

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR (SHIFT CONTROL ECU POWER SOURCE CIRCUIT) 

Result: 

OK 

See step  4

Pre-procedure1

• Turn the ignition switch to ON.

• Measure the voltage according to the value(s) in the table below.

  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

  *a	Component with harness connected (Transmission Floor Shift Assembly (Shift Control ECU))

  Standard Voltage

  Tester Connection	Switch Condition	Specified Condition	Result
  C35-3 (IGR) - C35-9 (E1)	Ignition switch ON	11 to 14 V	V
  C35-1 (IGP) - C35-9 (E1)	Ignition switch ON	11 to 14 V	V

  HINT: 

  As there might be an intermittent malfunction in the transmission floor shift assembly (shift control ECU) power source circuit, inspect the following even if the measured voltage is as specified:

  • Installation condition of fuse(s) (before removing fuse(s)) (IGR, IGP circuits)
  • Fuse condition (before and after removing fuse(s)) (IGR, IGP circuits)
  • Connection condition of connectors (IGR, IGP circuits)
  • Wire harness condition (IGR, IGP circuits)
  • Wire harness condition (GND circuit)

  Result

  Proceed to
  OK
  NG

Post-procedure1

• Turn the ignition switch OFF.

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR (SHIFT CONTROL ECU POWER SOURCE CIRCUIT) 

Result: 

OK 

See step  5

Pre-procedure1

• Disconnect the B29 ECM connector.
  NOTE:

  • Before disconnecting the connector, check that it is not loose or disconnected.
  • Check that each connector between the ECM and transmission floor shift assembly (shift control ECU) is not loose or disconnected.
• Disconnect the C35 transmission floor shift assembly connector.
  NOTE:

  • Before disconnecting the connector, check that it is not loose or disconnected.
  • Check the terminals of the connector for deformation and corrosion.
• Disconnect the B56 shift control actuator assembly connector.

• Measure the resistance according to the value(s) in the table below.

  Standard Resistance

  Tester Connection	Switch Condition	Specified Condition	Result
  B29-49 (CAN+) - C35-21 (CA3H)	Ignition switch off	Below 1 Ω	Ω
  B29-48 (CAN-) - C35-6 (CA3L)	Ignition switch off	Below 1 Ω	Ω
  C35-21 (CA3H) - Body ground and other terminals	Ignition switch off	10 kΩ or higher	kΩ
  C35-6 (CA3L) - Body ground and other terminals	Ignition switch off	10 kΩ or higher	kΩ

  NOTE:

  Make sure that each connector between the ECM and transmission floor shift assembly (shift control ECU) is not loose or disconnected and its terminals are not deformed or corroded.

  Result

  Proceed to
  OK
  NG

Post-procedure1

• Connect the B56 shift control actuator assembly connector.
• Connect the C35 transmission floor shift assembly connector.
• Connect the B29 ECM connector.

Result: 

OK 

REPLACE TRANSMISSION FLOOR SHIFT ASSEMBLY (SHIFT CONTROL ECU). Refer to  REMOVAL [10/2022 - ] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR