Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Lost Communication with Alternator Missing Message (P161A87)
DESCRIPTION
The ECM communicates with the generator assembly via LIN communication. If a LIN communication error is detected, the ECM stores this DTC.
| DTC No. | Detection Item | DTC Detection Condition | Trouble Area | Warning Indicate | Memory | Note |
|---|---|---|---|---|---|---|
| P161A87 | Lost Communication with Alternator Missing Message | Generator assembly or ECM communication stops for approximately 17 minutes or more with the engine switch on (IG). (1 trip detection logic) |
| Charge warning light comes on | DTC stored | SAE Code: P161A |
WIRING DIAGRAM
CAUTION / NOTICE / HINT
NOTICE:
- Inspect the fuses for circuits related to this system before performing the following inspection procedure.
- Before replacing the ECM, refer to Service Bulletin.
PROCEDURE
| 1. | CHECK CHARGING SYSTEM |
(a) Check the charging system.
Click here 
| NG |  | REPAIR OR REPLACE CHARGING SYSTEM |
|
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| 2. | CHECK HARNESS AND CONNECTOR (ECM - GENERATOR ASSEMBLY) |
(a) Disconnect the D2 ECM connector.
(b) Disconnect the D48 generator assembly connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| D48-2 (LIN) - D2-135 (LIN) | Always | Below 1 Ω |
| D48-2 (LIN) or D2-135 (LIN) - Body ground | Always | 10 kΩ or higher |
| OK | | REPLACE GENERATOR ASSEMBLY |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
On-vehicle Inspection
ON-VEHICLE INSPECTION PROCEDURE 1. CHECK BATTERY CONDITION NOTICE: If the battery is weak or if the engine is difficult to start, recharge the battery and perform inspections again before returning th ...
Charging Failure
PROCEDURE 1. CHECK GENERATOR PULLEY WITH CLUTCH (ON-VEHICLE INSPECTION) (a) Start the engine and visually check that the generator rotor assembly (fan) in the generator assembly is operating. ...
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Lexus RX (RX 350L, RX450h) 2016-{YEAR} Owners Manual
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Lexus RX (RX 350L, RX450h) 2016-{YEAR} Repair Manual
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