Engine Immobiliser System (w/ Smart Key System)

ENGINE IMMOBILISER: ENGINE IMMOBILISER SYSTEM (w/ Smart Key System): B2785: Communication Malfunction between ECUs Connected by LIN

DTC B2785 - Communication Malfunction between ECUs Connected by LIN

DESCRIPTION

The certification ECU (smart key ECU assembly) monitors communication between all the ECUs connected to the certification ECU (smart key ECU assembly) system LIN bus lines. When the certification ECU (smart key ECU assembly) detects errors in communication with all the ECUs connected to the certification ECU (smart key ECU assembly) system LIN bus lines at a set interval and 3 times in a row, DTC B2785 will be output.






WIRING DIAGRAM





INSPECTION PROCEDURE

NOTE: When using Techstream with the ignition switch off to troubleshoot:

Connect Techstream to the vehicle, and turn the courtesy switch on and off at 1.5-second intervals until communication between the tester and vehicle begins.

PROCEDURE

1. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - EACH ECU)
(a) Disconnect the D40 connector.
(b) Disconnect the D31 connector.
(c) Disconnect the 1E connector.
(d) Disconnect the D11 connector.




(e) Measure the resistance according to the value(s) in the table below.
Standard resistance:





(f) Measure the resistance according to the value(s) in the table below.
Standard voltage:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
2. CHECK FOR DTC
(a) Connect the D40 connector.
(b) Connect the D31 connector.
(c) Connect the D11 connector.
(d) Check for DTC.
Result:






B -- REPLACE MAIN BODY ECU (INSTRUMENT PANEL JUNCTION BLOCK)
A -- Continue to next step.
3. CHECK FOR DTC
(a) Connect the 1E connector.
(b) Disconnect the D11 connector.
(c) Check for DTC.
Result:






B -- REPLACE STEERING LOCK ECU (STEERING LOCK ACTUATOR ASSEMBLY)
A -- Continue to next step.
4. CHECK FOR DTC
(a) Connect the D11 connector.
(b) Disconnect the D31 connector.
(c) Check for DTC.
Result:






B -- REPLACE ID CODE BOX (IMMOBILISER CODE ECU)
A -- REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)
5. REPLACE MAIN BODY ECU (INSTRUMENT PANEL JUNCTION BLOCK)
(a) Replace the main body ECU (instrument panel junction block assembly) with a normally-functioning or a new one.
NEXT -- Continue to next step.
6. CHECK FOR DTC
(a) Recheck for DTC.
Result:






B -- REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)
A -- END
7. REPLACE STEERING LOCK ECU (STEERING LOCK ACTUATOR ASSEMBLY)
(a) Replace the steering lock ECU (steering lock actuator assembly) with a new one Removal.
NEXT -- Continue to next step.
8. CHECK FOR DTC
(a) Recheck for DTC.
Result:






B -- REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)
A -- END
9. REPLACE ID CODE BOX (IMMOBILISER CODE ECU)
(a) Replace the ID code box (immobiliser code ECU) with a new one.
NEXT -- Continue to next step.
10. CHECK FOR DTC
(a) Recheck for DTC.
Result:






B -- REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)
A -- END