Diagnostic Test

1. Connect the scan tool to another vehicle and check if the scan tool communicates properly.

   Does the scan tool communicate properly with another vehicle?

   Yes 

   • Go To  2

   No 

   • Contact the scan tool support.

For complete CAN-FD 6  and CAN-FD 7  systems wiring at the Data Link connector, Refer to the appropriate Wiring Information  .

1. Make sure the terminals in the DLC are properly secured and are not damaged.

   Were any problems found?

   Yes 

   • Repair the DLC or terminals, as needed. Once the repair is complete, check the communication between the scan tool and the vehicle.

   No 

   • Go To  3

1. Connect the (special tool #CH7002, Break Out Box, J1962, 16-Way)
   NOTE:

   Do not connect the scan tool to the Break Out Box.

2. Turn the ignition on.
3. Measure the voltage on the DLC Fused (B+) circuit at the Break Out Box.

   Is the voltage above 10.0 volts?

   Yes 

   • Go To  4

   No 

   • Using the wiring diagrams as a guide, Inspect for an open fuse. If the fuse is open, check the DLC Fused (B+) circuit for a short to ground and repair, if needed. If the fuse is OK, repair the DLC Fused (B+) circuit for an open or high resistance.

1. Turn the ignition off.
2. Measure the resistance of the DLC Ground circuits between ground and the Breakout Box.

   Is the resistance above 3.0 Ohms?

   Yes 

   • Repair the DLC Ground circuits for an open or high resistance.

   No 

   • Go To  5

1. Turn the ignition on.
2. Measure and record the voltage on the CAN-FD 6 Bus (+) circuit at the Breakout Box.
3. Measure and record the voltage on the CAN-FD 6 Bus (-) circuit at the Breakout Box.
4. Compare the recorded results to the above CAN BUS OPERATIONAL VOLTAGES table.

   Are the CAN-FD 6 Bus (+) and (-) circuit voltages within the specified values?

   Yes 

   • Go To  6

   No 

   • Voltage is BELOW the specified value:  Go To  7
   • Voltage is ABOVE the specified value:  Repair the short to voltage on the CAN-FD 6 Bus circuit(s).
   • Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .

1. Measure and record the voltage on the CAN-FD 7 Bus (+) circuit at the Breakout Box.
2. Measure and record the voltage on the CAN-FD 7 Bus (-) circuit at the Breakout Box.
3. Compare the results to the above CAN BUS OPERATIONAL VOLTAGES table.

   Are the CAN-FD 7 Bus (+) and (-) circuit voltages within the specified values?

   Yes 

   • Contact scan tool support.

   No 

   • Voltage is BELOW the specified value:  Go To  7
   • Voltage is ABOVE the specified value:  Repair the short to voltage on the CAN-FD 7 Bus circuit(s).
   • Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .

1. Turn the ignition off.
2. Disconnect the SGW Module harness connector.
3. Measure the resistance of the CAN-FD 6 Bus (+) circuit between the Breakout Box and the SGW Module harness connector.
4. Measure the resistance of the CAN-FD 6 Bus (-) circuit between the Breakout Box and the SGW Module harness connector.
5. Measure the resistance of the CAN-FD 7 Bus (+) circuit between the Breakout Box and the SGW Module harness connector.
6. Measure the resistance of the CAN-FD 7 Bus (-) circuit between the Breakout Box and the SGW Module harness connector.

   Is the resistance above 3.0 Ohms for any of the CAN-FD Bus circuits?

   Yes 

   NOTE:

   The CAN communication network wires typically contain 33-50 twists per meter (one twist for every 20 to 30.3 mm, or one twist for every 0.75 to 1.2 inches). It is important to maintain the twisted pair configuration whenever servicing a dual-wire communication network.

   The length of the circuit wires are also important in communication systems so both wires need to maintain their same lengths or it can result in communication fault / error.

   Due to the twisted pair configuration and length of wiring, an overlay harness is NOT  a recommended repair.

   • Check the CAN-FD Bus wiring and electrical connectors for signs of water intrusion, corrosion, pushed out or bent terminals, and correct pin tension and repair as necessary. If no problems are found, repair the open or high resistance in the CAN-FD Bus circuit(s).
   • Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .

   No 

   • Go To  8

1. Check for continuity between ground and the CAN-FD 6 Bus (+) circuit at the SGW Module harness connector.
2. Check for continuity between ground and the CAN-FD 6 Bus (-) circuit at the SGW Module harness connector.
3. Check for continuity between ground and the CAN-FD 7 Bus (+) circuit at the SGW Module harness connector.
4. Check for continuity between ground and the CAN-FD 7 Bus (-) circuit at the SGW Module harness connector.

   Is there continuity between ground and any of the CAN-FD Bus circuits?

   Yes 

   NOTE:

   The CAN communication network wires typically contain 33-50 twists per meter (one twist for every 20 to 30.3 mm, or one twist for every 0.75 to 1.2 inches). It is important to maintain the twisted pair configuration whenever servicing a dual-wire communication network.

   The length of the circuit wires are also important in communication systems so both wires need to maintain their same lengths or it can result in communication fault / error.

   Due to the twisted pair configuration and length of wiring, an overlay harness is NOT  a recommended repair.

   • Repair the short to ground in the CAN-FD Bus circuit(s).
   • Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .

   No 

   • Go To  9

1. Check for continuity between the CAN-FD 6 Bus (+) circuit and the CAN-FD 6 Bus (-) circuit at the SGW Module harness connector.

   Is there continuity between the CAN-FD 6 Bus (+) circuit and the CAN-FD 6 Bus (-) circuit?

   Yes 

   NOTE:

   The CAN communication network wires typically contain 33-50 twists per meter (one twist for every 20 to 30.3 mm, or one twist for every 0.75 to 1.2 inches). It is important to maintain the twisted pair configuration whenever servicing a dual-wire communication network.

   The length of the circuit wires are also important in communication systems so both wires need to maintain their same lengths or it can result in communication fault / error.

   Due to the twisted pair configuration and length of wiring, an overlay harness is NOT  a recommended repair.

   • Repair the short between the CAN-FD 6 Bus (+) and (-) circuits.
   • Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .

   No 

   • Go To  10

1. Check for continuity between the CAN-FD 7 Bus (+) circuit and the CAN-FD 7 Bus (-) circuit at the SGW Module harness connector.

   Is there continuity between the CAN-FD 7 Bus (+) circuit and the CAN-FD 7 Bus (-) circuit?

   Yes 

   NOTE:

   The CAN communication network wires typically contain 33-50 twists per meter (one twist for every 20 to 30.3 mm, or one twist for every 0.75 to 1.2 inches). It is important to maintain the twisted pair configuration whenever servicing a dual-wire communication network.

   The length of the circuit wires are also important in communication systems so both wires need to maintain their same lengths or it can result in communication fault / error.

   Due to the twisted pair configuration and length of wiring, an overlay harness is NOT  a recommended repair.

   • Repair the short between the CAN-FD 7 Bus (+) and (-) circuits.
   • Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .

   No 

   • Go To  11

1. Check the fuse for an open. If the fuse is open, make sure to check for a short to ground prior to replacing the fuse.
2. The ignition must be off when performing a load test on a circuit.
3. Isolate the circuit(s) by disconnecting the Electronic Control Unit (ECU) and all other harness connectors containing the circuit(s) being tested.
4. Connect the positive lead of the load test tool to the positive side of the Battery (A). Refer to the diagram below.
5. Using an approved back probe tool, connect the negative lead of the load test tool to the circuit being tested at the ECU harness connectors (B).
6. Using an approved back probe tool and a fused jumper wire, connect the circuit being tested to the negative side of the Battery or a known good ground at the other ECU/Power Distribution Center (PDC) harness connector (C and D).
7. The bulb on the load test tool should be illuminated and bright if there is no resistance in the circuit.
   NOTE:

   Why load test a circuit?  A load test is used to determine if a circuit is capable of carrying the amperage needed to perform properly. The 3156 bulb in the load tool illustrated, is a simple but effective method of testing circuit functionality. A 3156 Bulb has approximately 6.0 Ohms of resistance when the bulb is powered  and draws approximately 2.0 amps of current. Read the CIRCUIT LOAD TESTING PROCEDURE for information on building a simple load test tool and for additional load testing information and alternative methods of load testing or voltage drop testing a circuit. Refer to CIRCUIT LOAD TESTING PROCEDURES .