3508C, 3512C, and 3516C Locomotive Engines Caterpillar


CAN Data Link - Test

Usage:

3508C F1X
System Operation Description:

Use this procedure to troubleshoot the CAN data link if a problem with the wiring is suspected.

The CAN data link is used for communication between the following modules: engine's Electronic Control Module (ECM), customer devices and various display modules. Two 120 Ohm terminating resistors must be installed in the wiring harness in order for the CAN data link to function properly.



Illustration 1g01258113
Typical schematic


Illustration 2g01381785
P1 ECM connector
(P1-34) CAN data link −
(P1-42) Shield for the CAN data link
(P1-50) CAN data link +


Illustration 3g01234146
Location of ECM connectors


Illustration 4g01258177
Connector "B"
(Terminal 16) CAN data link +
(Terminal 17) CAN data link −
(Terminal 25) Shield for the CAN data link


Illustration 5g01258179
Connector "G"
(Terminal 20) CAN data link +
(Terminal 21) CAN data link −
(Terminal 5) Shield for the CAN data link

Test Step 1. Inspect the Electrical Connectors and the Wiring

  1. Turn the main disconnect switch to the OFF position.

  2. Thoroughly inspect the ECM connector J1/P1. Inspect all of the connectors to other modules on the CAN data link. Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect" for details.

  3. Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the circuit.

  4. Check the ECM connector (allen head screw) for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.

  5. Check the harness and the wiring for abrasion and for pinch points.

Expected Result:

All of the connectors, pins and sockets are completely coupled and/or inserted and the harness and wiring are free of corrosion, of abrasion and of pinch points.

Results:

  • OK - The harness and connectors appear to be OK. Proceed to Test Step 3.

  • Not OK - The connectors and/or wiring are not OK.

    Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled.

    Verify that the repair eliminates the problem.

    STOP

Test Step 2. Verify the Proper Installation of the Terminating Resistors

  1. Verify that the terminating resistors are installed on the ends of the data link.

  2. Disconnect the J1/P1 ECM connector and measure the resistance between P1-50 (CAN data link +) and P1-34 (CAN data link -).

Expected Result:

The resistance is approximately 60 ± 3 Ohms.

Results:

  • OK - The resistance is within the range. Proceed to Test Step 3.

  • Not OK - The resistance is approximately 120 ± 6 Ohms. A terminating resistor is missing or damaged.

    Repair: If a termination resistor is missing, install the missing resistor. If both resistors are present, measure the resistance between pin A and pin B of the termination resistor. The resistance should measure 120 ± 3 Ohms. Replace the termination resistor if the resistance is not 120 ± 3 Ohms.

    STOP

Test Step 3. Check for Shorts in the Harness

  1. Disconnect the ECM connector J1/P1 at the engine ECM.

  2. Disconnect the ECM connector J2/P2 at the engine ECM.

  3. Disconnect any control modules from the CAN data link.

  4. Disconnect Caterpillar Electronic Technician (ET) from the service tool connector.

  5. Measure the resistance from P1-50 to every terminal on ECM connectors P1 and P2.

  6. Measure the resistance from P1-50 to the chassis ground.

  7. Measure the resistance from P1-34 to every terminal on ECM connectors P1 and P2.

  8. Measure the resistance from P1-34 to the chassis ground.

Expected Result:

The resistance measurements indicate an open circuit.

Results:

  • OK - The resistance measurements indicate an open circuit. Proceed to Test Step 4.

  • Not OK - The resistance measurements do not indicate an open circuit. There is a short circuit in the harness.

    Repair: Repair the connectors or wiring and/or replace the connectors or wiring.

    STOP

Test Step 4. Check for an Open in the Harness

  1. Use a suitable piece of wire to create a short circuit between the data link wires at one of the control modules on the CAN data link.

  2. Measure the resistance between P1-50 and P1-34.

  3. Measure the resistance at the connectors of any other control modules.

Expected Result:

The resistance measurement indicates a short circuit.

Results:

  • OK - The resistance measurement indicates a short circuit. The CAN data link is OK.

    Repair: If the problem is intermittent, perform the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect".

    STOP

  • Not OK - The resistance measurement does not indicate a short circuit. There is an open circuit in the harness or connectors.

    Repair: Repair the connectors or wiring and/or replace the connectors or wiring.

    STOP

Caterpillar Information System:

G3304B and G3306B Engines CAN Data Link - Test
3406E, C-10, C-12, C-15, C-16 Truck Engines Crankshaft End Play - Test
G3304B and G3306B Engines Turbocharger - Install
G3304B and G3306B Engines Turbocharger - Remove
C13 Engine for Combat and Tactical Vehicles Electronic Control Wiring Group
G3304B and G3306B Engines Aftercooler - Install
C13 Engine for Combat and Tactical Vehicles Electronic Control Module
793F and 793F CMD Off-Highway Truck Power Train Position Sensor (Hoist Control)
G3304B and G3306B Engines Aftercooler - Remove
2009/05/25 Correction to Schematics for the Control Group {1408}
Instructions For Converting Uninterruptible Power Supplys With Hall Effect Probes To The G3.5 Load Cell{4480} Instructions For Converting Uninterruptible Power Supplys With Hall Effect Probes To The G3.5 Load Cell{4480}
UPS Bearing Type I to G3.5 Conversion{4480} UPS Bearing Type I to G3.5 Conversion{4480}
C9.3 Tier 4 Final Engines Exhaust Gas Valve (NRS)
CX35-P800-C18I and CX35-P800-C27I Petroleum Power Train Packages and CX35-P800 Petroleum Transmission Diagnostic Code List
G3304B and G3306B Engines Turbocharger - Disassemble
G3304B and G3306B Engines Turbocharger - Assemble
CX35-P800-C18I and CX35-P800-C27I Petroleum Power Train Packages and CX35-P800 Petroleum Transmission MID 027 - CID 1401 - FMI 03
CX35-P800-C18I and CX35-P800-C27I Petroleum Power Train Packages and CX35-P800 Petroleum Transmission MID 027 - CID 1401 - FMI 05
CX35-P800-C18I and CX35-P800-C27I Petroleum Power Train Packages and CX35-P800 Petroleum Transmission MID 027 - CID 1401 - FMI 06
3500B Generator Set Engines Vibration Damper Guard
G3304B and G3306B Engines Water Temperature Regulator - Remove
G3304B and G3306B Engines Water Temperature Regulator - Install
3508C, 3512C, and 3516C Locomotive Engines Cat Data Link - Test
C9.3 Tier 4 Final Engines General Information
Back to top
The names Caterpillar, John Deere, JD, JCB, Hyundai or any other original equipment manufacturers are registered trademarks of the respective original equipment manufacturers. All names, descriptions, numbers and symbols are used for reference purposes only.
CH-Part.com is in no way associated with any of the manufacturers we have listed. All manufacturer's names and descriptions are for reference only.