DTC B2301-87: Lost Communication with Gear Shift Control Module "A" (Line) Missing Message [08/2023 - ]: Procedure
WARNING: This page is about a different car, the 2025 Lexus RX 350, 2024 Lexus RX 350, and 2023 Lexus RX 350. However, it is still accessible from the selected car via links, so may be relevant.
- CHECK FOR DTC
- Check for DTCs.
Body Electrical > Sub Battery System > Trouble Codes
Result
Result Proceed to B2301-87 is output A B2301-87 is not output B
Result:
B
USE SIMULATION METHOD TO CHECK. Refer to HOW TO PROCEED WITH TROUBLESHOOTING [10/2022 - ]
Result:
A
See step 2
- Check for DTCs.
- CHECK HARNESS AND CONNECTOR (TRANSMISSION FLOOR SHIFT ASSEMBLY (SHIFT CONTROL ECU) - INTEGRATED CAPACITOR (INTEGRATION CONTROL SUPPLY))
Pre-procedure1
- Disconnect the C35 transmission floor shift assembly (shift control ECU) connector.
- Measure the voltage according to the value(s) in the table below.
Standard Voltage
Tester Connection Condition Specified Condition Result C35-20 (BUBO) - Body ground Ignition switch ON 5 V or higher V C35-20 (BUBO) - Body ground After the ignition switch is left off for 5 minutes Below 1 V V Result
Proceed to OK NG
Post-procedure1
- None
Result:
OK
REPLACE TRANSMISSION FLOOR SHIFT ASSEMBLY (SHIFT CONTROL ECU). Refer to REMOVAL [10/2022 - ]
Result:
NG
See step 3
- CHECK HARNESS AND CONNECTOR (INTEGRATED CAPACITOR (INTEGRATION CONTROL SUPPLY) - TRANSMISSION FLOOR SHIFT ASSEMBLY (SHIFT CONTROL ECU))
Pre-procedure1
- Disconnect the cable from the negative (-) auxiliary battery terminal.
- Disconnect the H191 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 H191-14 (BR) - C35-20 (BUBO) Ignition switch off Below 10 Ω Ω H191-14 (BR) - Body ground Ignition switch off 10 kΩ or higher kΩ Result
Proceed to OK NG
Post-procedure1
- None
Result:
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
Result:
OK
See step 4
- CHECK HARNESS AND CONNECTOR (INTEGRATED CAPACITOR (INTEGRATION CONTROL SUPPLY) - TRANSMISSION FLOOR SHIFT ASSEMBLY (SHIFT CONTROL ECU))
Pre-procedure1
- Reconnect the cable to the negative (-) auxiliary battery terminal.
- Measure the voltage according to the value(s) in the table below.
Standard Voltage
Tester Connection Condition Specified Condition Result H191-14 (BR) - Body ground Ignition switch off Below 1 V V Result
Proceed to OK NG
Post-procedure1
- None
Result:
OK
REPLACE INTEGRATED CAPACITOR (INTEGRATION CONTROL SUPPLY). Refer to REMOVAL [08/2023 - ]
Result:
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR