Diesel Data: Automotive Repair

Short in CAN Bus Lines








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

Short in CAN Bus Lines

DESCRIPTION

The CAN bus wires are considered to be shorted when the resistance between terminals 6 (CANH) and 14 (CANL) of the DLC3 is below 54 Ohms.






WIRING DIAGRAM









INSPECTION PROCEDURE
NOTICE:
- Turn the power switch off before measuring the resistances of CAN bus main wires and CAN bus branch wires.
- After the power switch is turned off, check that the key reminder warning system and lighting system are not operating.
- Before measuring the resistance, leave the vehicle as is for at least 1 minute and do not operate the power switch, any other switches, or the doors. If any doors need to be opened in order to check connectors, open the doors and leave them open.
HINT: Operating the power switch, any other switches, or a door triggers related ECU and sensor communication on the CAN. This communication will cause the resistance value to change.

PROCEDURE

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




(a) Turn the power switch off.
(b) Disconnect DLC3 branch wire gray connector E62 from the No. 1 CAN J/C "B" side (without earth terminal).
NOTICE:
- Before disconnecting the connector, make a note of where it is connected.
- Reconnect the connector to its original position.




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





(d) Reconnect DLC3 branch wire connector E62 to the No. 1 CAN J/C "B" side (without earth terminal).
NG -- REPLACE DLC3 BRANCH WIRE OR CONNECTOR
OK -- Continue to next step.
2. CHECK FOR SHORT IN CAN BUS WIRES (NO. 1 CAN J/C SIDE)




(a) Disconnect CAN main bus wire white connector E42 from the No. 1 CAN J/C "A" side (with earth terminal).




(b) Connect the probes of an ohmmeter to terminals 6 (CANH) and 14 (CANL) of the DLC3.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:






OK -- CHECK FOR SHORT IN CAN BUS WIRES
NG -- Continue to next step.
3. CHECK FOR SHORT IN CAN BUS WIRES (NO. 1 CAN J/C BRANCH WIRE)




(a) Reconnect CAN main bus wire connector E42 to the No. 1 CAN J/C "A" side (with earth terminal).
(b) Connect the probes of an ohmmeter to terminals 6 (CANH) and 14 (CANL) of the DLC3.
(c) While observing the resistance value shown on the tester, disconnect connectors E44, E45, E46 and E63 from the No. 1 CAN J/C one by one until the resistance becomes normal (between 54 and 69 Ohms).
HINT: Disconnect the branch wire connectors other than those of the DLC3.

















NOTICE: Do not reconnect the disconnected connectors until this inspection is complete because there may be a short in 2 or more branch wires.

Result:





(d) When there is a short in one or more of the branch wires:
(1) Reconnect all of the connectors to the No. 1 CAN J/C, except for the one that was disconnected last (the short-circuited bus wire). Check that the resistance shown on the tester is normal (between 54 and 69 Ohms) to confirm that there is a short in one branch wire only.
HINT:
- The connectors connected to the No. 1 CAN J/C can be distinguished according to the color of the communication bus wires and the shape of the connectors.
- Reconnecting the connectors to non-specified positions on the No. 1 CAN J/C does not affect system operation. However, it is preferred to reconnect the connectors to their specified positions to avoid negative effects on the wiring such as tension on the wiring harnesses, and to make future maintenance easier.

B -- RECONNECT CONNECTOR
A -- Continue to next step.
4. CHECK FOR SHORT IN CAN BUS WIRES (COMBINATION METER MAIN BUS WIRE)




(a) Disconnect CAN main bus wire white connector E43 from the No. 1 CAN J/C "B" side (without earth terminal).
- 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 -- REPLACE NO. 1 CAN J/C
OK -- Continue to next step.
5. RECONNECT CONNECTOR
(a) Reconnect CAN main bus wire connector E43 to the No. 1 CAN J/C "B" side (without earth terminal).
NEXT -- Continue to next step.
6. CHECK FOR SHORT IN CAN BUS WIRES (COMBINATION METER)




(a) Disconnect combination meter connector F1.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:





HINT: If the resistance changes to 108 to 132 Ohms when the connector is disconnected, there may be a short in the combination meter.

NG -- REPLACE CAN BUS MAIN WIRE (COMBINATION METER MAIN BUS WIRE)
OK -- REPLACE COMBINATION METER
7. CHECK FOR SHORT IN CAN BUS WIRES




(a) Reconnect CAN main bus wire connector E42 to the No. 1 CAN J/C "A" side (with earth terminal).
(b) Disconnect No. 2 CAN J/C connector E41 (rear of the vehicle).




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






OK -- CHECK FOR SHORT IN CAN BUS WIRES (A/C AMPLIFIER BRANCH WIRE)
NG -- Continue to next step.
8. CHECK FOR SHORT IN CAN BUS WIRES (NO. 2 CAN J/C - NO. 3 CAN J/C)




(a) Reconnect No. 2 CAN J/C connector E41 (front of the vehicle).
(b) Disconnect No. 2 CAN J/C connector A40 (rear of the vehicle).
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- CHECK FOR SHORT IN CAN BUS WIRES (POWER STEERING ECU BRANCH WIRE)
OK -- Continue to next step.
9. CHECK FOR SHORT IN CAN BUS WIRES (HV CONTROL ECU MAIN BUS WIRE)




(a) Disconnect No. 2 CAN J/C connector A40.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- CHECK FOR SHORT IN CAN BUS WIRES (HV CONTROL ECU MAIN BUS WIRE)
OK -- Continue to next step.
10. CHECK FOR SHORT IN CAN BUS WIRES (SKID CONTROL ECU - NO. 2 CAN J/C)




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






OK -- REPLACE NO. 2 CAN J/C
NG -- Continue to next step.
11. CHECK FOR SHORT IN CAN BUS WIRES (SKID CONTROL ECU - NO. 2 CAN J/C)




(a) Disconnect skid control ECU connector A74.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:





HINT: Measure the resistance with No. 2 CAN J/C connector A40 disconnected.

OK -- REPLACE SKID CONTROL ECU
NG -- REPLACE SKID CONTROL ECU BRANCH WIRE OR CONNECTOR
12. CHECK FOR SHORT IN CAN BUS WIRES (HV CONTROL ECU MAIN BUS WIRE)




(a) Disconnect HV control ECU connector A61.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:





HINT: Measure the resistance with No. 2 CAN J/C connector A40 disconnected.

NG -- REPLACE CAN BUS MAIN WIRE OR CONNECTOR (HV CONTROL ECU - NO. 2 CAN J/C)
OK -- REPLACE HYBRID VEHICLE CONTROL ECU
13. CHECK FOR SHORT IN CAN BUS WIRES (A/C AMPLIFIER BRANCH WIRE)




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






NG -- CHECK FOR SHORT IN CAN BUS WIRES (A/C AMPLIFIER - NO. 2 CAN J/C)
OK -- Continue to next step.
14. CHECK FOR SHORT IN CAN BUS WIRES (RADIO AND NAVIGATION ASSEMBLY BRANCH WIRE)




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






NG -- CHECK FOR SHORT IN CAN BUS WIRES (RADIO AND NAVIGATION ASSEMBLY BRANCH WIRE)
OK -- REPAIR OR REPLACE ACCESSORY GATEWAY BRANCH WIRE OR CONNECTOR
15. CHECK FOR SHORT IN CAN BUS WIRES (A/C AMPLIFIER - NO. 2 CAN J/C)




(a) Disconnect A/C amplifier connector E38.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPLACE A/C AMPLIFIER BRANCH WIRE OR CONNECTOR
OK -- REPLACE A/C AMPLIFIER
16. CHECK FOR SHORT IN CAN BUS WIRES (POWER STEERING ECU BRANCH WIRE)




(a) Reconnect CAN main bus wire connector A40 to the No. 2 CAN J/C (rear of the vehicle).
(b) Disconnect power steering ECU branch wire connector A41 from the No. 3 CAN J/C (front of the vehicle).




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






OK -- CHECK FOR SHORT IN CAN BUS WIRES (POWER STEERING ECU BRANCH WIRE)
NG -- Continue to next step.
17. CHECK FOR SHORT IN CAN BUS WIRES (NO. 2 CAN J/C - NO. 3 CAN J/C)




(a) Reconnect power steering ECU branch wire connector A41 to the No. 2 CAN J/C (front of the vehicle).
(b) Disconnect CAN main bus wire connector A42 from the No. 3 CAN J/C (front of the vehicle).
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPLACE CAN BUS MAIN WIRE OR CONNECTOR (NO. 2 CAN J/C - NO. 3 CAN J/C)
OK -- Continue to next step.
18. CHECK FOR OPEN IN CAN BUS MAIN WIRE (NO. 1 CAN J/C - NO. 3 CAN J/C)




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






NG -- REPLACE CAN BUS MAIN WIRE OR CONNECTOR (NO. 1 CAN J/C - NO. 2 CAN J/C)
OK -- REPLACE NO. 3 CAN J/C
19. CHECK FOR SHORT IN CAN BUS WIRES (POWER STEERING ECU BRANCH WIRE)




(a) Disconnect the A66 power steering ECU connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:





HINT: Measure the resistance with No. 3 CAN J/C connector A41 disconnected.

OK -- REPLACE POWER STEERING ECU ASSY
NG -- REPLACE POWER STEERING ECU BRANCH WIRE OR CONNECTOR
20. CHECK FOR SHORT IN CAN BUS WIRES (RADIO AND NAVIGATION ASSEMBLY BRANCH WIRE)




(a) Disconnect the F12 radio and navigation assembly connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPLACE POWER STEERING ECU BRANCH WIRE OR CONNECTOR
OK -- REPLACE RADIO AND NAVIGATION ASSEMBLY
21. RECONNECT CONNECTOR
(a) Reconnect the connector for the short-circuited branch wire to the No. 1 CAN J/C (the connector that caused the bus wire resistance to become normal (between 54 and 69 Ohms) when it was disconnected).
NEXT -- Continue to next step.
22. CHECK FOR SHORT IN CAN BUS WIRES




(a) Disconnect the connector that includes terminals CANH and CANL from the ECU (or sensor) to which the short-circuited branch wire is connected. Symptom Related Diagnostic Procedures
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:





HINT: If the resistance becomes normal (between 54 and 69 Ohms) when the connector is disconnected from the ECU (or sensor), there may be a short in the ECU (or sensor).

NG -- REPLACE CORRESPONDING ECU OR SENSOR BRANCH WIRE OR CONNECTOR
OK -- REPLACE CORRESPONDING ECU OR SENSOR