DTC P161A-87: Lost Communication with Alternator Missing Message [10/2024 - ]: 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 CHARGING SYSTEM
Refer to ON-VEHICLE INSPECTION [10/2022 - ]
Result
Proceed to OK NG Result:
NG
REPAIR OR REPLACE CHARGING SYSTEM
Result:
OK
See step 2
- CHECK HARNESS AND CONNECTOR (ECM - GENERATOR ASSEMBLY)
Pre-procedure1
- Disconnect the ECM connector.
- Disconnect the generator assembly connector.
- Disconnect the battery state sensor assembly connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition Result A16-44 (LIN) - B33-2 (LIN) Always Below 1 Ω Ω A16-44 (LIN), B33-2 (LIN) or A40-2 (LIN) - Body ground Always 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 3
- CLEAR DTC
Pre-procedure1
- Check for DTCs, and then write them down.
Powertrain > Engine > Trouble Codes
Post-procedure1
- Turn the ignition switch off and wait 30 seconds.
Result:
NEXT
See step 4
- Check for DTCs, and then write them down.
- CHECK DTC OUTPUT
Pre-procedure1
- Start the engine.
- Allow the engine to idle for approximately 17 minutes or more.
- Check for DTCs.
Powertrain > Engine > Trouble Codes
Result
Result Proceed to DTCs are not output A P161A-87 and P162B-87 are output B Only P161A-87 is output C
Post-procedure1
- None.
Result:
A
CHECK FOR INTERMITTENT PROBLEMS. Refer to HOW TO PROCEED WITH TROUBLESHOOTING [10/2022 - ]
Result:
B
REPLACE ECM. Refer to REMOVAL [10/2022 - ]
Result:
C
REPLACE GENERATOR ASSEMBLY. Refer to REMOVAL [10/2022 - ]