DTC U0291-87: Lost Communication with Gear Shift Control Module "B" Missing Message [11/2021 - ]: Procedure

1. According to the display on the GTS, select "Health Check".
2. Check for DTCs.

   Result

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

3. Turn the ignition switch off.

Result: 

B 

GO TO DTC CHART. Refer to  DIAGNOSTIC TROUBLE CODE CHART [11/2021 - 03/2024]  , or Refer to  DIAGNOSTIC TROUBLE CODE CHART [03/2024 - ] 

Result: 

A 

See step  2

1. Check for DTCs.

   Powertrain > Hybrid Control > Trouble Codes 

   Result

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

2. Turn the ignition switch off.

Result: 

B 

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

Result: 

A 

See step  3

1. Disconnect the shift control actuator assembly (shift control actuator ECU) connector.
2. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   B78-8 (BAT1) - Body ground	Ignition switch off	11 to 14 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)) (BAT1 circuit)
   • Fuse condition (before and after removing fuse(s)) (BAT1 circuit)
   • Connection condition of connectors (BAT1 circuit)
   • Wire harness condition (BAT1 circuit)
   • Wire harness condition (GND circuit)

   Result

   Proceed to
   OK
   NG

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

Result: 

NG 

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

Result: 

OK 

See step  4

1. Disconnect the shift control actuator assembly (shift control actuator ECU) connector.
2. Turn the ignition switch to ON.
3. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   B77-5 (IGCT) - Body ground	Ignition switch off	11 to 14 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)) (IGCT circuit)
   • Fuse condition (before and after removing fuse(s)) (IGCT circuit)
   • Connection condition of connectors (IGCT circuit)
   • Wire harness condition (IGCT circuit)
   • Wire harness condition (GND circuit)

   Result

   Proceed to
   OK
   NG

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

Result: 

NG 

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

Result: 

OK 

See step  5

1. 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 repair information because this may cause a malfunction.

2. 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 control actuator ECU) is not loose or disconnected.
3. Disconnect the shift control actuator assembly (shift control 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.
4. Disconnect the D39 transmission floor shift assembly (shift control ECU) connector.
5. Disconnect the D2 radio and display receiver assembly connector.
6. Disconnect the d1 mobile wireless charger cradle assembly connector. (w/ Wireless Charger System)
7. Disconnect the D22 combination meter assembly connector. (w/o Headup Display)
8. Disconnect the z14 battery ECU assembly connector.
9. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   D67-10 (CA4H) - B77-4 (CA3H)	Ignition switch off	Below 1 Ω
   D67-23 (CA4L) - B77-3 (CA3L)	Ignition switch off	Below 1 Ω
   B77-4 (CA3H) - Body ground and other terminals	Ignition switch off	10 kΩ or higher
   B77-3 (CA3L) - Body ground and other terminals	Ignition switch off	10 kΩ or higher

   NOTE:

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

   Result

   Proceed to
   OK
   NG

10. Reconnect the battery ECU assembly connector.
11. Reconnect the combination meter assembly connector. (w/o Headup Display)
12. Reconnect the mobile wireless charger cradle assembly connector. (w/ Wireless Charger System)
13. Reconnect the radio and display receiver assembly connector.
14. Reconnect the transmission floor shift assembly (shift control ECU) connector.
15. Reconnect the shift control actuator assembly (shift control actuator ECU) connector.
16. Reconnect the hybrid vehicle control ECU connector.

Result: 

OK 

REPLACE SHIFT CONTROL ACTUATOR ASSEMBLY (SHIFT CONTROL ACTUATOR ECU). Refer to  REMOVAL [11/2021 - ] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR