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Home >> Lexus >> 2012 >> IS 250 AWD V6-2.5L (4GR-FSE) >> Repair and Diagnosis >> Powertrain Management >> Computers and Control Systems >> Information Bus >> Testing and Inspection >> Component Tests and General Diagnostics >> Open in CAN Main Bus Line

Open in CAN Main Bus Line





CAN COMMUNICATION: CAN COMMUNICATION SYSTEM: Open in CAN Main Bus Line
- Open in CAN Main Bus Line

DESCRIPTION

There may be an open circuit in the CAN main bus line and/or the DLC3 branch line when the resistance between terminals 6 (CANH) and 14 (CANL) of the DLC3 is 70 Ohms or more.





This malfunction is not related to the lines of a CAN branch or to ECUs or sensors connected a CAN branch.

WIRING DIAGRAM





INSPECTION PROCEDURE

NOTICE:
* Because the order of diagnosis is important to allow correct diagnosis, make sure to begin troubleshooting using How to Proceed with Troubleshooting when CAN communication system related DTCs are output How to Proceed With Troubleshooting.
* After performing repairs, perform the procedure listed in DTC Reproduction Method and confirm that the DTCs are not output again.
* DTC Reproduction Method: Turn the engine switch on (IG), wait at least 60 seconds, and then drive the vehicle at a speed of 60 km/h (38 mph) or more for at least 2 seconds.
* After the repair, perform CAN Bus Check and check that all the ECUs and sensors connected to the CAN communication system are displayed Diagnosis System.

PROCEDURE

1. CHECK DLC3

(a) Turn the engine switch off.

(b) Measure the resistance according to the value(s) in the table below.





Standard Resistance:





NOTICE:
When the measured value is 133 Ohms or more and a CAN communication system DTC is output, there may be a fault besides disconnection of the DLC3 branch line. For that reason, troubleshooting should be performed again from "HOW TO PROCEED WITH TROUBLESHOOTING" How to Proceed With Troubleshooting after repairing the trouble area.

B -- REPAIR OR REPLACE DLC3 BRANCH LINE OR CONNECTOR (CANH, CANL)
A -- Continue to next step.

2. CHECK FOR OPEN IN CAN BUS MAIN LINE (CAN BUS CHECK)

(a) Perform "CAN Bus Check" using the Techstream Diagnosis System.

Result:





B -- CHECK FOR OPEN IN CAN BUS MAIN LINE (GATEWAY ECU - CAN LH J/C)

C -- CHECK FOR OPEN IN CAN BUS MAIN LINE (ECM - CAN LH J/C)
A -- Continue to next step.

3. CHECK FOR OPEN IN CAN BUS MAIN LINE (ECM - CAN LH J/C)

(a) Turn the engine switch off.





(b) Disconnect the ECM connector (A5).

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:





NG -- REPAIR OR REPLACE CAN BUS MAIN LINE OR CONNECTOR (ECM - CAN LH J/C)

OK -- REPLACE ECM

4. CHECK FOR OPEN IN CAN BUS MAIN LINE (GATEWAY ECU - CAN LH J/C)

(a) Turn the engine switch off.





(b) Disconnect the gateway ECU connector (J76).

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:





OK -- REPLACE GATEWAY ECU
NG -- Continue to next step.

5. RECONNECT CONNECTOR

(a) Reconnect the gateway ECU connector (J76).

NEXT -- Continue to next step.

6. CHECK FOR OPEN IN CAN BUS MAIN LINE (CAN RH J/C - GATEWAY ECU)

(a) Disconnect the CAN main bus line connector (J84) from the CAN RH J/C B side (w/o earth terminal).





NOTICE:
* Before disconnecting the connector, make a note of where it is connected.
* Reconnect the connector to its original position.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:





NG -- REPAIR OR REPLACE CAN BUS MAIN LINE OR CONNECTOR (CAN RH J/C - GATEWAY ECU)

OK -- REPAIR OR REPLACE CAN BUS MAIN LINE OR CONNECTOR (CAN LH J/C - CAN RH J/C)

7. CHECK FOR OPEN IN CAN BUS MAIN LINE (ECM - CAN LH J/C)

(a) Turn the engine switch off.





(b) Disconnect the ECM connector (A5).

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:





OK -- REPLACE ECM
NG -- Continue to next step.

8. RECONNECT CONNECTOR

(a) Reconnect the ECM connector (A5).

NEXT -- Continue to next step.

9. CHECK FOR OPEN IN CAN BUS MAIN LINE (GATEWAY ECU - CAN LH J/C)

(a) Disconnect the gateway ECU connector (J76).





(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:





OK -- REPLACE GATEWAY ECU
NG -- Continue to next step.

10. RECONNECT CONNECTOR

(a) Reconnect the gateway ECU connector (J76).

NEXT -- Continue to next step.

11. CHECK FOR OPEN IN CAN BUS MAIN LINE (CAN RH J/C - GATEWAY ECU)

(a) Disconnect the CAN main bus line connector (J84) from the CAN RH J/C B side (w/o earth terminal).





NOTICE:
* Before disconnecting the connector, make a note of where it is connected.
* Reconnect the connector to its original position.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:





NG -- REPAIR OR REPLACE CAN BUS MAIN LINE OR CONNECTOR (CAN RH J/C - GATEWAY ECU)
OK -- Continue to next step.

12. RECONNECT CONNECTOR

(a) Reconnect the CAN main bus line connector (J84) to the CAN RH J/C B side (w/o earth terminal).

NEXT -- Continue to next step.

13. CHECK FOR OPEN IN CAN BUS MAIN LINE (ECM - CAN LH J/C)

(a) Disconnect the CAN main bus line connector (J2) from the CAN LH J/C A side (w/ earth terminal).





(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:





NG -- REPAIR OR REPLACE CAN BUS MAIN LINE OR CONNECTOR (ECM - CAN LH J/C)

OK -- REPAIR OR REPLACE CAN BUS MAIN LINE OR CONNECTOR (CAN LH J/C - CAN RH J/C)
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