KIT-SEAL 1U3131 - Caterpillar

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 to communicate information from the Electronic Control Module (ECM) to other control modules and display modules that are connected to the data link. The ECM broadcasts engine information and diagnostics for the electronic system. This ECM supports the following parameters for the broadcast over the CAN data link:
Table 1
Parameters for Data Link Broadcast
Parameter Name Parameter Group Number (PGN) Suspect Parameter Number (SPN)
Percent Load 61443 92
Engine Oil Pressure 65263 100
Battery Voltage 65271 168
Boost Pressure 65270 102
Engine Coolant Temperature 65262 110
Fuel Pressure 65263 94
Fuel Rate 65266 (1)
Engine Speed 61444 190
Engine Hours 65253 (1)
Throttle Position 61443 91
Atmospheric Pressure 65269 108
Desired Engine Speed 65247 515
Oil Filter Differential Pressure 65276 99
Fuel Filter Differential Pressure 65276 95
Aftercooler Temperature 65262 52
Left Exhaust Temperature 65176 1180
Right Exhaust Temperature 65176 1181
Right Air Filter Restriction 64976 2809
Left Air Filter Restriction 65270 107
Crankcase Pressure 65263 101
Unfiltered Oil Pressure (absolute pressure) 65170 1208
Left Turbocharger Inlet Pressure 65177 1177
Right Turbocharger Inlet Pressure 65177 1176
Startup Mode 61444 1675
Overspeed Test Switch 65252 2812
Air Shutoff 65252 2813
General Alarm Output Status 65252 2814
Inlet Air Temperature 65270 105
Fuel Consumption 65257 250
(1) No SPN is available at the present time.Two 120 Ohm terminating resistors must be installed in the wiring harness in order for the CAN data link to function properly.
Illustration 1 g01227891
Typical schematic for the CAN data link
Test Step 1. Inspect the Electrical Connectors and the Wiring
Remove power from the ECM.
Thoroughly inspect the ECM connectors J1/P1 and J2/P2. Inspect all of the connectors to other modules on the CAN data link. Refer to the diagnostic functional test Troubleshooting, "Inspecting Electrical Connectors" for details.
Illustration 2 g01233666
P1 ECM connector
(P1-50) CAN data link +
(P1-34) CAN data link −
(P1-42) Shield for the CAN data link
Illustration 3 g01233672
Customer connector
(Terminal 31) CAN data link +
(Terminal 32) CAN data link −
(Terminal 33) Shield for the CAN data link
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the circuit.
Check the allen head screw for each ECM connector for the proper torque. Refer to Troubleshooting, "Inspecting Electrical Connectors" for the correct torque value.
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 2.
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.STOPTest Step 2. Verify the Proper Installation of the Terminating Resistors
Verify that the terminating resistors are installed on the ends of the data link.
Disconnect J1/P1 ECM connector. Measure the resistance between terminals P1-50 (CAN data link +) and P1-34 (CAN data link -).