DTC U0291-87: Lost Communication with Gear Shift Control Module "B" Missing Message [08/2023 - ]: Procedure

Pre-procedure1

• According to the display on the GTS, select "Health Check".

• Check for DTCs.

  Result

  Result	Proceed to
  No DTCs are output.	A
  DTCs are output.	B

Post-procedure1

• Turn the ignition switch off.

Result: 

B 

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

Result: 

A 

See step  2

Pre-procedure1

• None.

• Check for DTCs.

  Powertrain > Hybrid Control > Trouble Codes 

  Result

  Result	Proceed to
  Only U0291-87 is output	A
  U0291-87 and U1176-87 are output	B

Post-procedure1

• Turn the ignition switch off.

Result: 

B 

SHIFT CONTROL ACTUATOR ASSEMBLY (SHIFT ACTUATOR ECU) POWER SOURCE CIRCUIT FAILURE 

Result: 

A 

See step  3

Pre-procedure1

• Disconnect the shift control actuator assembly (shift actuator ECU) connectors.

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

  Standard Voltage

  Tester Connection	Condition	Specified Condition	Result
  B56-1 (MA1) - Body ground	Ignition switch off	11 to 14 V	V
  B57-8 (BAT1) - Body ground	Ignition switch off	11 to 14 V	V

  HINT: 

  As there might be an intermittent malfunction, inspect the following items even if the measured voltage is as specified.

  • Installation condition of fuse(s) (before removing fuse(s)) (MA1, BAT1 circuit)
  • Fuse condition (before and after removing fuse(s)) (MA1, BAT1 circuit)
  • Connection condition of connectors (MA1, BAT1 circuit)
  • Wire harness condition (MA1, BAT1 circuit)
  • Wire harness condition (GND circuit)

  Result

  Proceed to
  OK
  NG

Post-procedure1

• Reconnect the shift control actuator assembly (shift actuator ECU) connector.

Result: 

NG 

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

Result: 

OK 

See step  4

Pre-procedure1

• Disconnect the shift control actuator assembly (shift actuator ECU) 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
  B56-5 (IGS1) - Body ground	Ignition switch ON	11 to 14 V	V

  HINT: 

  As there might be an intermittent malfunction, inspect the following items even if the measured voltage is as specified.

  • Installation condition of fuse(s) (before removing fuse(s)) (IGS1 circuit)
  • Fuse condition (before and after removing fuse(s)) (IGS1 circuit)
  • Connection condition of connectors (IGS1 circuit)
  • Wire harness condition (IGS1 circuit)
  • Wire harness condition (GND circuit)

  Result

  Proceed to
  OK
  NG

Post-procedure1

• Turn the ignition switch off.
• Reconnect the shift control actuator assembly (shift actuator ECU) connector.

Result: 

NG 

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

Result: 

OK 

See step  5

Pre-procedure1

• Check that the service plug grip is not installed.
  NOTE:

  After removing the service plug grip, do not turn the ignition switch to ON (READY), unless instructed by the appropriate service information because this may cause a malfunction.

• Disconnect the hybrid vehicle control ECU connector.
  NOTE:

  • Before disconnecting the connector, check that it is not loose or disconnected.
  • Check that each connector between the hybrid vehicle control ECU and shift control actuator assembly (shift actuator ECU) is not loose or disconnected.
• Disconnect the shift control actuator assembly (shift actuator ECU) 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 C35 transmission floor shift assembly (shift control ECU) connector.
• Disconnect the H124 electric vehicle charger 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 battery ECU assembly connector.

  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

  Standard Resistance

  Tester Connection	Condition	Specified Condition	Result
  C59-9 (CA4H) - B56-4 (CA3H)	Ignition switch off	Below 1 Ω	Ω
  C59-22 (CA4L) - B56-3 (CA3L)	Ignition switch off	Below 1 Ω	Ω
  B56-4 (CA3H) - Body ground and other terminals	Ignition switch off	10 kΩ or higher	kΩ
  B56-3 (CA3L) - Body ground and other terminals	Ignition switch off	10 kΩ or higher	kΩ

  NOTE:

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

  Result

  Proceed to
  OK
  NG

Post-procedure1

• Reconnect the battery ECU assembly connector.
• Reconnect the Electric vehicle charger assembly connector.
• Reconnect the transmission floor shift assembly (shift control ECU) connector.
• Reconnect the shift control actuator assembly (shift actuator ECU) connector.
• Reconnect the hybrid vehicle control ECU connector.

Result: 

OK 

REPLACE SHIFT CONTROL ACTUATOR ASSSEMBLY (SHIFT ACTUATOR ECU). Refer to  REMOVAL [08/2023 - ] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR