Check CAN Bus Lines for Short Circuit
NETWORKING: CAN COMMUNICATION SYSTEM: Check CAN Bus Lines for Short Circuit
- Check CAN Bus Lines for Short Circuit
DESCRIPTION
There may be a short circuit between the V bus main lines and/or CAN branch lines when the resistance between terminals 6 (CANH) and 14 (CANL) of the DLC3 is below 54 Ohms.
* *1: for Navigation receiver type
* *2: for Radio and display type (w/ Intuitive parking assist system)
* *3: for Radio and display type (w/o Intuitive parking assist system)
* *4: w/ Intuitive parking assist system
* *5: Separate type yaw rate sensor
WIRING DIAGRAM
INSPECTION PROCEDURE
NOTICE:
* Before measuring the resistance of the CAN bus, turn the power switch off and leave the vehicle for 1 minute or more without operating the key, switches or opening or closing the doors. After that, disconnect the cable from the negative (-) auxiliary battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.
* After turning the power switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary battery terminal notices before proceeding with work Service Precautions.
* 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 DTC check procedure and confirm that the DTCs are not output again.
* DTC check procedure: Turn the power switch on (IG), turn the cruise control main switch on, turn the blind spot monitor main switch on, wait at least 60 seconds and then drive the vehicle at a speed of 20 km/h (12 mph) or more for at least 11 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.
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.
* Even after DTCs are cleared, if a DTC is stored again after driving the vehicle for a while, the malfunction may be occurring due to vibration of the vehicle. In such a case, wiggling the ECUs or wire harness while performing the inspection below may help determine the cause of the malfunction.
* Connectors that connect to the CAN junction connector can be distinguished by color of their CAN bus lines. When the connectors have been disconnected from the CAN junction connector, reconnecting the connectors to non-original positions on the CAN junction connector does not affect system performance. However, it is preferred to reconnect the connectors to their original positions to avoid negative effects on the wiring such as tension on the wiring harnesses, and to make future maintenance easier.
PROCEDURE
1. CHECK FOR SHORT IN CAN BUS LINES (DLC3 BRANCH LINE)
(a) Disconnect the cable from the negative (-) auxiliary battery terminal.
(b) Disconnect the DLC3 branch line connector (I96) from the CAN junction LH connector.
Text in Illustration
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:
Text in Illustration
NG -- REPAIR OR REPLACE CAN BRANCH LINE CONNECTED TO DLC3
OK -- Continue to next step.
2. CHECK FOR SHORT IN CAN BUS LINES (BRANCH LINE)
(a) Reconnect the DLC3 branch line connector (I96) to the CAN junction LH connector.
(b) Connect the probes of an ohmmeter to terminals 6 (CANH) and 14 (CANL) of the DLC3.
Text in Illustration
(c) While observing the resistance value shown on the tester, disconnect connectors (I110, I95, I97, I109, I159, I100, I107, I106, I102, I111 and I103) from the CAN junction LH connector or CAN junction RH connector one by one until the resistance becomes normal (between 54 and 69 Ohms).
HINT
Disconnect the branch line connectors other than those of the DLC3.
Text in Illustration
Text in Illustration
Wiring Color
*1: Separate type yaw rate sensor
Text in Illustration
Wiring Color
*1: for Navigation receiver type
*2: for Radio and display type (w/ Intuitive parking assist system)
*3: for Radio and display type (w/o Intuitive parking assist system)
*4: w/ Intuitive parking assist system
NOTICE:
Do not reconnect the disconnected connectors until this inspection is complete because there may be a short in 2 or more branch lines.
Result:
(d) When there is a short in one or more of the branch lines:
(1) Reconnect all of the connectors to the CAN J/C, except for the one that was disconnected last (the short-circuited bus line). Check that the resistance shown on the tester is normal (between 54 and 69 Ohms) to confirm that there is a short in the one branch line only.
HINT
* Connectors that connect to the CAN junction connector can be distinguished by the color of their CAN bus lines.
* Reconnecting the connectors to non-original positions on the CAN junction connector does not affect system performance. However, it is preferred to reconnect the connectors to their original positions to avoid negative effects on the wiring such as tension on the wiring harnesses, and to make future maintenance easier.
B -- CHECK FOR SHORT IN CAN BUS LINES (ECU, SENSOR)
A -- Continue to next step.
3. CHECK FOR SHORT IN CAN BUS LINES (COMBINATION METER ASSEMBLY MAIN BUS LINE)
(a) Disconnect the combination meter assembly main bus line connector (I94) from the CAN junction LH connector.
Text in Illustration
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:
Text in Illustration
Result:
B -- CHECK FOR SHORT IN CAN BUS LINES (COMBINATION METER ASSEMBLY)
A -- Continue to next step.
4. CHECK FOR SHORT IN CAN BUS LINES (ECM MAIN BUS LINE)
(a) Disconnect the ECM main bus line connector (I104) from the CAN junction RH connector.
Text in Illustration
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:
Text in Illustration
HINT
Measure the resistance with the combination meter assembly main bus line connector (I94) disconnected.
Result:
B -- CHECK FOR SHORT IN CAN BUS LINES (ECM)
A -- Continue to next step.
5. CHECK FOR SHORT IN CAN BUS LINES (CAN J/C LH)
(a) Disconnect the CAN main bus line connector (I93) from the CAN junction LH connector.
Text in Illustration
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:
Text in Illustration
NG -- REPLACE CAN JUNCTION LH CONNECTOR
OK -- Continue to next step.
6. CHECK FOR SHORT IN CAN BUS LINES (CAN J/C LH - CAN J/C RH)
(a) Reconnect the CAN main bus line connector (I93) to the CAN junction LH connector.
(b) Disconnect the CAN main bus line connector (I101) from the CAN junction RH connector.
Text in Illustration
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:
Text in Illustration
NG -- REPAIR OR REPLACE CAN MAIN BUS LINES (CAN J/C LH - CAN J/C RH)
OK -- REPLACE CAN JUNCTION RH CONNECTOR
7. CHECK FOR SHORT IN CAN BUS LINES (ECU, SENSOR)
(a) Reconnect the connector for the short-circuited branch line to the CAN J/C (the connector that caused the bus line resistance to become normal (between 54 and 69 Ohms) when it was disconnected).
(b) Disconnect the connector that includes the DLC3 connected CAN lines (such as CANH and CANL) from the ECU (or sensor) to which the short-circuited branch line is connected CAN Communication System.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
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 -- REPAIR OR REPLACE CORRESPONDING ECU OR SENSOR BRANCH LINES OR CONNECTOR
OK -- REPLACE CORRESPONDING ECU OR SENSOR
8. CHECK FOR SHORT IN CAN BUS LINES (COMBINATION METER ASSEMBLY)
(a) Reconnect the combination meter assembly main bus line connector (I94) to the CAN junction LH connector.
(b) Disconnect the combination meter assembly connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
HINT
If the resistance becomes normal (between 108 to 132 Ohms) when the connector is disconnected, there may be a short in the combination meter assembly.
NG -- REPAIR OR REPLACE CAN MAIN BUS LINES (COMBINATION METER ASSEMBLY MAIN LINES)
OK -- REPLACE COMBINATION METER ASSEMBLY Removal
9. CHECK FOR SHORT IN CAN BUS LINES (ECM)
(a) Reconnect the ECM main bus line connector (I104) to the CAN junction RH connector.
(b) Disconnect the ECM connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
HINT
* Measure the resistance with the combination meter assembly main bus line connector (I94) disconnected.
* If the resistance changes to 1 MOhms or more when the connector is disconnected, there may be a short in the ECM.
NG -- REPAIR OR REPLACE CAN MAIN BUS LINES (ECM MAIN LINES)
OK -- REPLACE ECM Removal