Lexus NX: Communication Malfunction between ECUs Connected by LIN (B2785)
DESCRIPTION
The certification ECU intermittently monitors the LIN communication bus between the components related to certification. DTC B2785 is stored when a malfunction in the LIN communication bus between the components related to certification is detected 3 times consecutively.
| DTC No. | Detection Item | DTC Detection Condition | Trouble Area |
|---|---|---|---|
| B2785 | Communication Malfunction between ECUs Connected by LIN | The certification ECU detects a malfunction in the LIN communication bus between components related to certification 3 times consecutively. |
|
WIRING DIAGRAM
CAUTION / NOTICE / HINT
NOTICE:
- When using the Techstream with the power switch off to troubleshoot:
- Connect the Techstream to the vehicle, and turn a courtesy light switch on and off at 1.5 second intervals until communication between the Techstream and vehicle begins.
- Before replacing the certification ECU (smart key ECU assembly), ID code box (immobiliser code ECU) or steering lock actuator assembly, refer to the engine immobiliser system.
PROCEDURE
| 1. | CLEAR DTC |
(a) Clear the DTCs.
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|
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| 2. | CHECK FOR DTC |
(a) Check for DTCs.
Click here
| DTC B2785 is not output | .gif) | USE SIMULATION METHOD TO CHECK |
|
| 3. | CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU [SMART KEY ECU ASSEMBLY] - ID CODE BOX [IMMOBILISER CODE ECU] OR STEERING LOCK ACTUATOR ASSEMBLY) |
(a) Disconnect the I53 certification ECU (smart key ECU assembly) connector.
(b) Disconnect the I26 ID code box (immobiliser code ECU) connector.
(c) Disconnect the I2 steering lock actuator assembly connector.
(d) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| I53-6 (LIN) - I2-5 (LIN) | Always | Below 1 Ω |
| I53-6 (LIN) - I26-2 (LIN1) | Always | Below 1 Ω |
| I53-6 (LIN) - Body ground | Always | 10 kΩ or higher |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
| 4. | CLEAR DTC |
(a) Clear the DTCs.
Click here
|
| 5. | CHECK FOR DTC |
(a) Disconnect the I2 steering lock actuator assembly connector.
(b) Check for DTCs.
Click here
| DTC B2785 is output | | REPLACE STEERING LOCK ACTUATOR ASSEMBLY |
|
| 6. | CLEAR DTC |
(a) Clear the DTCs.
Click here
|
| 7. | CHECK FOR DTC |
(a) Disconnect the I26 ID code box (immobiliser code ECU) connector.
(b) Check for DTCs.
Click here
| DTC B2785 is not output | | REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) |
| DTC B2785 is output | | REPLACE ID CODE BOX (IMMOBILISER CODE ECU) |
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