3412E, C30 and C32 Marine Engines Caterpillar


CAN Data Link Circuit - Test

Usage:

3412E 9KS
System Operation Description:

Table 1
Parameters for Data Link Broadcast    
Parameter     PGN     Bytes     Resolution (Offset)
   
Byte Order in Message     Transmission Rate    
Percent Load     61443     1     1%/bit
(0%)    
3     50 ms    
Battery Voltage     65271     2     0.05 V/bit
(0 V)    
5, 6     1.0 s    
Boost Pressure     65270     1     2 kPa/bit
(0 kPa)    
2     50 ms    
Coolant Temperature     65262     1     1 °C/bit
(-40 °C)    
1     50 ms    
Engine Hours     65253     4     0.05 hr/bit
(0 hr)    
1, 2, 3, 4     50 ms    
Engine Speed     61444     2     0.125 rpm/bit
(0 rpm)    
4, 5     15 ms    
Fuel Pressure     65263     1     4 kPa/bit
(0 kPa)    
1     50 ms    
Fuel Temperature     65262     1     1 °C/bit
(-40 °C)    
2     50 ms    
Fuel Rate     65266     2     0.05L/hr/bit
(0Lhr)    
1, 2     100 ms    
Inlet Manifold Temperature     65270     1     1 °C/bit
(-40 °C)    
3     50 ms    
Oil Pressure     65263     1     4 kPa/bit
(0 kPa)    
4     50 ms    
Oil Temperature     65262     2     0.03125 °C/bit
(-273 °C)    
3, 4     50 ms    
Transmission Pressure     65272     1     16 kPa/bit
(0 kPa)    
4     1.0 s    
Transmission Temperature     65272     2     0.03125 °C/bit
(-273 °C)    
5, 6     1.0 s    

The CAN Data Link is used to communicate information from the ECM in order to share engine information and diagnostics for the electronic system.




Illustration 1g00920215

Circuit for the CAN Data Link

Test Step 1. Inspect Electrical Connectors and Wiring

  1. Turn the keyswitch to the OFF/RESET position.

  1. Check the connectors and wiring for the following problems: damage, corrosion, abrasion and incorrect attachment. Pay close attention to the following areas:

    • J1/P1 ECM connector

    • J3/P3 Customer connector

    • Connectors for the J1939 Data Link

    • Engine wiring harness from the ECM to the customer connector

    Refer to Troubleshooting, "Electrical Connectors - Inspect" for more information.

Expected Result:

The connectors and wiring should be free of the following problems: damage, corrosion, abrasion and incorrect attachment.

Results:

  • OK - Proceed to Test Step 2.

  • Not OK -

    Repair: Repair the J1939 Data Link circuit. Verify that the repair eliminates the problem.

    Stop.

Test Step 2. Verify that Termination Resistors are Installed on the Ends of the Data Link

  1. Disconnect the P1 ECM connector from the ECM.

  1. Disconnect the J1939 Displays from the harness.

  1. Measure the resistance between P1:10 and P1:16 of the P1 ECM connector.

Expected Result:

The resistance should be 60 ohms ± 5%.

Results:

  • OK - Proceed to Test Step 3.

  • Not OK -

    Repair: The resistance equals 120 ohms ± 5%. A terminating resistor is missing. Refer to Illustration 1 and install the missing terminating resistor.

    Stop.

  • Not OK - Resistance is less than 50 ohms. Proceed to Test Step 3.

  • Not OK - Resistance is greater than 130 ohms. Proceed to Test Step 4.

Test Step 3. Verification of Number of Terminating Resistors

A terminating resistor should be installed at each end of the J1939 data link. Refer to Illustration 1 for the proper location.

Expected Result:

The J1939 Data Link circuit should contain two terminating resistors.

Results:

  • OK - Proceed to Test Step 4.

  • Not OK - Make the necessary changes in the circuit for the J1939 Data Link in order to ensure that the two terminating resistors are in the proper locations. Stop.

Test Step 4. Check for a Short in the CAN Data Link

  1. Disconnect the P1 ECM connector from the ECM.

  1. Disconnect the J1939 display modules.

  1. Remove the terminating resistors.

  1. Measure the resistance between the following pins.

    • P1:10 and P1:16

    • P1:10 and P1:15

    • P1:15 and P1:16

Expected Result:

The resistance should be greater than 20,000 ohms.

Results:

  • OK - There are no shorts in the wiring harness. Proceed to Test Step 5.

  • Not OK -

    Repair: There is a short in the harness. Make the necessary repairs. Verify that the repair eliminates the problem.

    Stop.

Test Step 5. Check for an Open Circuit at the J1939 Display

  1. Allow the components to remain disconnected.

  1. Make a short jumper with sockets.

  1. Install one end of the jumper on pin A of the J1939 Display connector.

  1. Install the other end of the jumper to pin B of the J1939 Display connector.

  1. Measure the resistance between P1:10 and P1:16.

Expected Result:

The resistance should be less than 10 ohms.

Results:

  • OK - Proceed to Test Step 6.

  • Not OK -

    Repair: There is an open circuit in the harness. Make the necessary repairs. Verify that the repair eliminates the problem.

    Stop.

Test Step 6. Check the J1939 Display

  1. Reconnect the P1 ECM connector.

  1. Remove the J1939 Display and take the display to the ECM.

  1. Disconnect the harness that is connected to the T for the ECM.

  1. Connect one end of a 165-0201 Cable to the T for the ECM.

  1. Connect the other end of the cable to the J1939 Display.

  1. Turn the keyswitch ON.

Expected Result:

The J1939 Display should operate properly.

Results:

  • OK -

    Repair: There is a problem in the wiring between the ECM and the J1939 Display. Make the necessary repairs. Verify that the repair eliminates the problem.

    Stop.

  • Not OK -

    Repair: There is an error in the Data Link with the J1939 Display. Connect the display to another engine. If the display operates properly, replace the ECM. If the display does not operate properly, replace the J1939 Display.

    Stop.

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.