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 |
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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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