Operation CHARM: Car repair manuals for everyone.
Home >> Toyota Truck >> 2008 >> Tundra 4WD V8-4.7L (2UZ-FE) >> Repair and Diagnosis >> Powertrain Management >> Computers and Control Systems >> Information Bus >> Testing and Inspection >> Component Tests and General Diagnostics >> Short to B+ in CAN Bus Line

Short to B+ in CAN Bus Line








CAN COMMUNICATION: CAN COMMUNICATION SYSTEM: Short to B+ in CAN Bus Line

Short to B+ in CAN Bus Line

DESCRIPTION

There may be a short circuit between the CAN bus line and +B when there is resistance between terminals 6 (CANH) and 16 (BAT) or terminals 14 (CANL) and 16 (BAT) of the DLC3.





HINT:
- *1: w/ Bus Buffer ECU
- *2: w/ 4WD

WIRING DIAGRAM









INSPECTION PROCEDURE

HINT: Operating the ignition switch, any 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 prevent airbag and seat belt pretensioner activation.

NOTE: After the ignition switch is turned OFF, the navigation system requires approximately 90 seconds to record various types of memory and settings. As a result, after turning the ignition switch OFF, wait 90 seconds or more before disconnecting the cable from the negative (-) battery terminal.

NEXT -- Continue to next step.
2. CHECK FOR SHORT TO B+ IN CAN BUS WIRE (DLC3 BRANCH WIRE)





(a) Disconnect the J86 No. 1 junction connector connector.
(b) Measure the resistance according to the value(s) in the table below.

Result





NG -- REPAIR OR REPLACE CAN BRANCH WIRE CONNECTED TO DLC3 (CANH, CANL)
OK -- Continue to next step.
3. CONNECT CONNECTOR
(a) Reconnect the J86 No. 1 junction connector connector.
NEXT -- Continue to next step.
4. CHECK FOR SHORT TO B+ IN CAN BUS WIRE (NO. 2 JUNCTION CONNECTOR SIDE)





(a) Disconnect the J93 No. 2 junction connector connector.
(b) Measure the resistance according to the value(s) in the table below.

Result





NG -- CONNECT CONNECTOR
OK -- Continue to next step.
5. CHECK FOR SHORT TO B+ IN CAN BUS WIRE (NO. 1 JUNCTION CONNECTOR - NO. 2 JUNCTION CONNECTOR)





(a) Disconnect the J94 No. 1 junction connector connector.
(b) Measure the resistance according to the value(s) in the table below.

Result





NG -- REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 1 JUNCTION CONNECTOR - NO. 2 JUNCTION CONNECTOR)
OK -- Continue to next step.
6. CONNECT CONNECTOR
(a) Reconnect the J94 No. 1 junction connector connector.
(b) Reconnect the J93 No. 2 junction connector connector.
NEXT -- Continue to next step.
7. CHECK FOR SHORT TO B+ IN CAN BUS WIRE (NO. 1 JUNCTION CONNECTOR - COMBINATION METER ECU)





(a) Disconnect the J84 No. 1 junction connector connector.
(b) Measure the resistance according to the value(s) in the table below.

Result





NG -- CHECK FOR SHORT TO B+ IN CAN BUS WIRE (COMBINATION METER ECU)
OK -- Continue to next step.
8. CHECK FOR SHORT TO B+ IN CAN BUS WIRE (NO. 1 JUNCTION CONNECTOR - MAIN BODY ECU)





(a) Disconnect the J96 No. 1 junction connector connector.
(b) Measure the resistance according to the value(s) in the table below.

Result





NG -- CHECK FOR SHORT TO B+ IN CAN BUS WIRE (MAIN BODY ECU)
OK -- Continue to next step.
9. CHECK FOR SHORT TO B+ IN CAN BUS WIRE (NO. 1 JUNCTION CONNECTOR - SKID CONTROL ECU WITH ACTUATOR)





(a) Disconnect the A46 No. 1 junction connector connector.
(b) Measure the resistance according to the value(s) in the table below.

Result





NG -- CHECK FOR SHORT TO B+ IN CAN BUS WIRE (SKID CONTROL ECU WITH ACTUATOR)
OK -- Continue to next step.
10. CHECK FOR SHORT TO B+ IN CAN BUS WIRE (NO. 1 JUNCTION CONNECTOR - STEERING ANGLE SENSOR)





(a) Disconnect the J87 No. 1 junction connector connector.
(b) Measure the resistance according to the value(s) in the table below.

Result





NG -- CHECK FOR SHORT TO B+ IN CAN BUS WIRE (STEERING ANGLE SENSOR)
OK -- Continue to next step.
11. CHECK FOR SHORT TO B+ IN CAN BUS WIRE (NO. 1 JUNCTION CONNECTOR - CENTER AIRBAG SENSOR)





(a) Disconnect the J83 No. 1 junction connector connector.
(b) Measure the resistance according to the value(s) in the table below.

Result





NG -- CHECK FOR SHORT TO B+ IN CAN BUS WIRE (CENTER AIRBAG SENSOR)
OK -- REPAIR OR REPLACE NO. 1 JUNCTION CONNECTOR
12. CHECK FOR SHORT TO B+ IN CAN BUS WIRE (COMBINATION METER ECU)





(a) Disconnect the J28 combination meter ECU connector.
(b) Measure the resistance according to the value(s) in the table below.

Result





NG -- REPAIR OR REPLACE CAN MAIN WIRE CONNECTED TO COMBINATION METER ECU (CANH, CANL)
OK -- REPLACE COMBINATION METER ASSEMBLY
13. CHECK FOR SHORT TO B+ IN CAN BUS WIRE (MAIN BODY ECU)





(a) Disconnect the J2 main body ECU connector.
(b) Measure the resistance according to the value(s) in the table below.

Result





NG -- REPAIR OR REPLACE CAN BRANCH WIRE CONNECTED TO MAIN BODY ECU (CANH, CANL)
OK -- REPLACE MAIN BODY ECU
14. CHECK FOR SHORT TO B+ IN CAN BUS WIRE (SKID CONTROL ECU WITH ACTUATOR)





(a) Disconnect the A17 skid control ECU with actuator connector.
(b) Measure the resistance according to the value(s) in the table below.

Result





NG -- REPAIR OR REPLACE CAN BRANCH WIRE CONNECTED TO SKID CONTROL ECU WITH ACTUATOR (CANH, CANL)
OK -- REPLACE SKID CONTROL ECU WITH ACTUATOR
15. CHECK FOR SHORT TO B+ IN CAN BUS WIRE (STEERING ANGLE SENSOR)





(a) Disconnect the J6 steering angle sensor connector.
(b) Measure the resistance according to the value(s) in the table below.

Result





NG -- REPAIR OR REPLACE CAN BRANCH WIRE CONNECTED TO STEERING ANGLE SENSOR (CANH, CANL)
OK -- REPLACE STEERING ANGLE SENSOR
16. CHECK FOR SHORT TO B+ IN CAN BUS WIRE (CENTER AIRBAG SENSOR)





(a) Disconnect the J46 center airbag sensor connector.
(b) Measure the resistance according to the value(s) in the table below.

Result





NG -- REPAIR OR REPLACE CAN BRANCH WIRE CONNECTED TO CENTER AIRBAG SENSOR (CANH, CANL)
OK -- REPLACE CENTER AIRBAG SENSOR
17. CONNECT CONNECTOR
(a) Reconnect the J93 No. 2 junction connector connector.
NEXT -- Continue to next step.
18. CHECK FOR SHORT TO B+ IN CAN BUS WIRE (NO. 2 JUNCTION CONNECTOR - AIR CONDITIONING AMPLIFIER)





(a) Disconnect the J85 No. 2 junction connector connector.
(b) Measure the resistance according to the value(s) in the table below.

Result





NG -- CHECK FOR SHORT TO B+ IN CAN BUS WIRE (AIR CONDITIONING AMPLIFIER)
OK -- Continue to next step.
19. CHECK FOR SHORT TO B+ IN CAN BUS WIRE (NO. 2 JUNCTION CONNECTOR - BUS BUFFER ECU)

NOTE: For vehicles without bus buffer ECU, go to "CHECK FOR SHORT TO B+ IN CAN BUS WIRE (NO. 2 JUNCTION CONNECTOR - 4WD CONTROL ECU)".





(a) Disconnect the J98 No. 2 junction connector connector.
(b) Measure the resistance according to the value(s) in the table below.

Result





NG -- CHECK FOR SHORT TO B+ IN CAN BUS WIRE (BUS BUFFER ECU)
OK -- Continue to next step.
20. CHECK FOR SHORT TO B+ IN CAN BUS WIRE (NO. 2 JUNCTION CONNECTOR - 4WD CONTROL ECU)

NOTE: For vehicles without 4WD, go to "CHECK FOR SHORT TO B+ IN CAN BUS WIRE (NO. 2 JUNCTION CONNECTOR - ECM)".





(a) Disconnect the J88 No. 2 junction connector connector.
(b) Measure the resistance according to the value(s) in the table below.

Result





NG -- CHECK FOR SHORT TO B+ IN CAN BUS WIRE (4WD CONTROL ECU)
OK -- Continue to next step.
21. CHECK FOR SHORT TO B+ IN CAN BUS WIRE (NO. 2 JUNCTION CONNECTOR - ECM)





(a) Disconnect the J92 No. 2 junction connector connector.
(b) Measure the resistance according to the value(s) in the table below.

Result





NG -- CHECK FOR SHORT TO B+ IN CAN BUS WIRE (ECM)
OK -- REPAIR OR REPLACE NO. 2 JUNCTION CONNECTOR
22. CHECK FOR SHORT TO B+ IN CAN BUS WIRE (AIR CONDITIONING AMPLIFIER)





(a) Disconnect the J19 air conditioning amplifier connector.
(b) Measure the resistance according to the value(s) in the table below.

Result





NG -- REPAIR OR REPLACE CAN BRANCH WIRE CONNECTED TO AIR CONDITIONING AMPLIFIER (CANH, CANL)
OK -- REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY
23. CHECK FOR SHORT TO B+ IN CAN BUS WIRE (BUS BUFFER ECU)





(a) Disconnect the J59 bus buffer ECU connector.
(b) Measure the resistance according to the value(s) in the table below.

Result





NG -- REPAIR OR REPLACE CAN BRANCH WIRE CONNECTED TO BUS BUFFER ECU (CANH, CANL)
OK -- REPLACE BUS BUFFER ECU
24. CHECK FOR SHORT TO B+ IN CAN BUS WIRE (4WD CONTROL ECU)





(a) Disconnect the A25 4WD control ECU connector.
(b) Measure the resistance according to the value(s) in the table below.

Result





NG -- REPAIR OR REPLACE CAN BRANCH WIRE CONNECTED TO 4WD CONTROL ECU (CANH, CANL)
OK -- REPLACE 4WD CONTROL ECU
25. CHECK FOR SHORT TO B+ IN CAN BUS WIRE (ECM)





(a) Disconnect the A24 ECM connector.
(b) Measure the resistance according to the value(s) in the table below.

Result





D -- REPAIR OR REPLACE CAN MAIN WIRE CONNECTED TO ECM (CANH, CANL)
C -- REPLACE ECM
B -- REPLACE ECM
A -- REPLACE ECM
pro multis · About Operation CHARM