DTC B2799-86: Engine Immobilizer System Signal (Some Circuit Quantity, Reported via Serial Data) Invalid [10/2022 - ]: Description

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.

If there is a communication malfunction between the ECM and ID code box (immobilizer code ECU), or when the communication ID codes do not match, the ECM stores this DTC.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	DTC Output from	Priority	Note
B2799-86	Engine Immobilizer System Signal (Some Circuit Quantity, Reported via Serial Data) Invalid	Either of the following conditions is met (1 trip detection logic*): A malfunction is detected in the communication or communication lines between the ECM and ID code box (immobilizer code ECU). The communication ID codes of the ECM and ID code box (immobilizer code ECU) do not match.	ID code box (immobilizer code ECU) ECM Harness or connector	Engine	A	DTC output confirmation operation (Perform either of the following): Start the engine and wait for 10 seconds. If there is a malfunction, the engine will stop (communication begins within 3 seconds of the engine start operation being performed, and DTCs are stored after 6 seconds). Connect the cable to the negative (-) auxiliary battery terminal, start the engine and wait for 10 seconds (communication begins within 3 seconds of the ignition switch being turned to ON, and DTCs are stored after 6 seconds).

*: Only output while a malfunction is present.

VEHICLE CONDITION AND FAIL-SAFE OPERATION WHEN MALFUNCTION DETECTED

Vehicle Condition when Malfunction Detected	Fail-safe Operation when Malfunction Detected
Engine cannot be started	-

RELATED DATA LIST AND ACTIVE TEST

DTC No.	Data List and Active Test
B2799-86	-