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Home >> Toyota Truck >> 2011 >> Sequoia 4WD V8-5.7L (3UR-FE) >> Repair and Diagnosis >> Powertrain Management >> Computers and Control Systems >> Information Bus >> Testing and Inspection >> Component Tests and General Diagnostics >> Short in CAN Bus Lines >> Part 1

Part 1





NETWORKING: CAN COMMUNICATION SYSTEM: Short in CAN Bus Lines
- Short in CAN Bus Lines

DESCRIPTION

There may be a short circuit between the CAN bus lines when the resistance between terminals 6 (CANH) and 14 (CANL) of the DLC3 is below 54 Ohms.





*1: w/ Bus Buffer ECU

*2: w/ 4WD

*3: w/ Air Suspension

*4: w/ Dynamic Laser Cruise Control System

WIRING DIAGRAM









INSPECTION PROCEDURE

HINT
Operating the ignition switch, any other switches or any doors triggers related ECU and sensor communication with the CAN, which causes resistance variation.

PROCEDURE

1. DISCONNECT CABLE FROM NEGATIVE BATTERY TERMINAL

(a) Disconnect the cable from the negative (-) battery terminal before measuring the resistances of the main wire and the branch wire.

CAUTION:
Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

NOTICE:
When disconnecting the cable, some systems need to be initialized after the cable is reconnected Repair Instruction - Initialization.

NEXT -- Continue to next step.

2. CHECK FOR SHORT IN CAN BUS WIRES (DLC3 BRANCH WIRE)

(a) Disconnect the H119 No. 1 junction connector.





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

Standard Resistance:





Text in Illustration





NG -- REPAIR OR REPLACE CAN BRANCH WIRE CONNECTED TO DLC3 (CANH, CANL)
OK -- Continue to next step.

3. CONNECT CONNECTOR

(a) Reconnect the H119 No. 1 junction connector.

NEXT -- Continue to next step.

4. CHECK FOR SHORT IN CAN BUS WIRES (NO. 2 JUNCTION CONNECTOR SIDE)

(a) Disconnect the H116 No. 2 junction connector.





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

Standard Resistance:





Text in Illustration





NG -- CHECK FOR SHORT IN CAN BUS WIRES (NO. 1 JUNCTION CONNECTOR - NO. 2 JUNCTION CONNECTOR)
OK -- Continue to next step.

5. CHECK FOR SHORT IN CAN BUS WIRES (NO. 2 JUNCTION CONNECTOR - AIR CONDITIONING AMPLIFIER)

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





Standard Resistance:





Text in Illustration





NG -- CHECK FOR SHORT IN CAN BUS WIRES (AIR CONDITIONING AMPLIFIER)
OK -- Continue to next step.

6. SYSTEM CHECK

(a) Check the vehicle specifications.

Result





B -- SYSTEM CHECK
A -- Continue to next step.

7. CHECK FOR SHORT IN CAN BUS WIRES (NO. 2 JUNCTION CONNECTOR - BUS BUFFER ECU)

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





Standard Resistance:





Text in Illustration





NG -- CHECK FOR SHORT IN CAN BUS WIRES (BUS BUFFER ECU)
OK -- Continue to next step.

8. SYSTEM CHECK

(a) Check the vehicle specifications.

Result





B -- CHECK FOR SHORT IN CAN BUS WIRES (NO. 2 JUNCTION CONNECTOR - ECM)
A -- Continue to next step.

9. CHECK FOR SHORT IN CAN BUS WIRES (NO. 2 JUNCTION CONNECTOR - 4WD CONTROL ECU)

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





Standard Resistance:





Text in Illustration





NG -- CHECK FOR SHORT IN CAN BUS WIRES (4WD CONTROL ECU)
OK -- Continue to next step.

10. CHECK FOR SHORT IN CAN BUS WIRES (NO. 2 JUNCTION CONNECTOR - ECM)

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





Standard Resistance:





Text in Illustration





NG -- CHECK FOR SHORT IN CAN BUS WIRES (ECM)

OK -- REPAIR OR REPLACE NO. 2 JUNCTION CONNECTOR

11. CHECK FOR SHORT IN CAN BUS WIRES (AIR CONDITIONING AMPLIFIER)

(a) Disconnect the H24 air conditioning amplifier connector.





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

Standard Resistance:





Text in Illustration





NG -- REPAIR OR REPLACE CAN BRANCH WIRE CONNECTED TO AIR CONDITIONING AMPLIFIER (CANH, CANL)

OK -- REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Removal

12. CHECK FOR SHORT IN CAN BUS WIRES (BUS BUFFER ECU)

(a) Disconnect the H66 bus buffer ECU connector.





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

Standard Resistance:





Text in Illustration





NG -- REPAIR OR REPLACE CAN BRANCH WIRE CONNECTED TO BUS BUFFER ECU (CAN+, CAN-)

OK -- REPLACE BUS BUFFER ECU

13. CHECK FOR SHORT IN CAN BUS WIRES (4WD CONTROL ECU)

(a) Disconnect the A28 4WD control ECU connector.





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

Standard Resistance:





Text in Illustration





NG -- REPAIR OR REPLACE CAN BRANCH WIRE CONNECTED TO 4WD CONTROL ECU (CANH, CANL)

OK -- REPLACE 4WD CONTROL ECU Removal

14. CHECK FOR SHORT IN CAN BUS WIRES (ECM)

(a) Disconnect the A27 ECM connector.





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

Standard Resistance:





Text in Illustration





Result





D -- REPLACE ECM Removal

C -- REPLACE ECM Removal

B -- REPLACE ECM Removal

A -- REPAIR OR REPLACE CAN MAIN WIRE CONNECTED TO ECM (CANH, CANL)

15. CHECK FOR SHORT IN CAN BUS WIRES (NO. 1 JUNCTION CONNECTOR - NO. 2 JUNCTION CONNECTOR)

(a) Disconnect the H119 No. 1 junction connector.





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

Standard Resistance:





Text in Illustration





NG -- REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 1 JUNCTION CONNECTOR - NO. 2 JUNCTION CONNECTOR)
OK -- Continue to next step.

16. CONNECT CONNECTOR

(a) Reconnect the H119 No. 1 junction connector.

(b) Reconnect the H116 No. 2 junction connector.

NEXT -- Continue to next step.

17. SYSTEM CHECK

(a) Check the vehicle specifications.

Result





B -- CHECK FOR SHORT IN CAN BUS WIRES (NO. 1 JUNCTION CONNECTOR - COMBINATION METER ECU)
A -- Continue to next step.

18. CHECK FOR SHORT IN CAN BUS WIRES (NO. 4 JUNCTION CONNECTOR SIDE)

(a) Disconnect the O41 No. 4 junction connector.





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

Standard Resistance:





Text in Illustration





NG -- CHECK FOR SHORT IN CAN BUS WIRES (NO. 1 JUNCTION CONNECTOR - NO. 4 JUNCTION CONNECTOR)
OK -- Continue to next step.

19. CONNECT CONNECTOR

(a) Reconnect the O41 No. 4 junction connector.

NEXT -- Continue to next step.

20. CHECK FOR SHORT IN CAN BUS WIRES (NO. 4 JUNCTION CONNECTOR - SUSPENSION CONTROL ECU)

(a) Disconnect the O42 No. 4 junction connector.





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

Standard Resistance:





Text in Illustration





NG -- CHECK FOR SHORT IN CAN BUS WIRES (SUSPENSION CONTROL ECU)
OK -- Continue to next step.
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