892049 Mariner SPACER

Illustration 1 g01368886
Schematic for the CAN data link
Illustration 2 g06112342
Connector locations for the CAN data link (typical left side rear engine view)
(1) Engine interface connector
(2) Service tool connector
(3) P1 ECM connector
Illustration 3 g01209797
Terminal locations at the P1 ECM connector that are associated with the CAN data link
(P1-34) CAN data link −
(P1-42) CAN shield
(P1-50) CAN data link +
Illustration 4 g01360095
Terminal locations at the engine interface connector that are associated with the CAN data link
(P1-16) CAN shield
(P1-17) CAN data link +
(P1-18) CAN data link −
Illustration 5 g01209794
Terminal locations at the service tool connector that are associated with the CAN data link
(Terminal C) CAN shield
(Terminal F) CAN data link −
(Terminal G) CAN data link +
Illustration 6 g01355248
Terminal locations at the service tool connector that are associated with the CAN data link
(Terminal C) CAN shield
(Terminal F) CAN data link −
(Terminal G) CAN data link +
Table 1
Troubleshooting Test Step Values Results
1. Inspect the Electrical Connectors and the Wiring
A. Remove the electrical power from the ECM.
B. Thoroughly inspect connectors (1), (2), and (3). Inspect all of the connectors that are associated with the CAN data link. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
C. Perform a 45 N (10 lb) pull test on each of the wires that are associated with the CAN data link.
D. Check the allen head screw on each ECM connector and on the customer connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
E. Check the wiring harnesses for abrasion, for corrosion and for pinch points.
All connectors, pins and sockets are completely coupled and/or inserted. The harness and wiring are free of corrosion, of abrasion and of pinch points.
Result: The harness and wiring appear to be OK. Proceed to Test Step 2.
Result: There is a problem in the wiring harness.
Repair the connectors and/or the wiring. Replace parts, if necessary. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled. Verify that the problem is resolved.
2. Verify the Proper Installation of the Termination Resistors
A. Remove the electrical power from the ECM.
B. Disconnect the display panel from the data link.
C. Disconnect the Caterpillar Electronic Technician (ET) from the service tool connector.
D. Disconnect the P1 ECM connector.
Wiggle the harness during the following measurements in order to reveal an intermittent condition.
E. Measure the resistance between terminals P1-50 (CAN Data Link +) and P1-34 (CAN Data Link -).
The resistance is between 57 and 63 Ohms.
Result: The resistance is between 57 and 63 Ohms. Proceed to Test Step 3.
Result: The resistance is between 114 Ohms and 126 Ohms. A termination resistor is missing
Verify that two termination resistors are connected to the data link. One resistor must be located on each end of the data link. The engine is shipped with one termination resistor that is installed between the ECM and the customer connector.
Refer to the appropriate electrical schematic in order to determine the missing resistor. Replace the missing resistor. Verify that the problem is resolved.
The resistance is less than 57 Ohms. There may be a short circuit in the harness. Proceed to Test Step 3.
The resistance is greater than 126 Ohms. There may be an open circuit in the harness. Proceed to Test Step 4.
Table 2
Resistance Measurements for the CAN Data Link
Connector and Terminal Terminal
P1-50 (CAN data link +) All of the other terminals on the P1 connector
Engine ground
P1-34 (CAN data link -) All of the other terminals on the P1 connector
Engine ground
Table 3
Troubleshooting Test Steps Values Results
3. Check the Harness for a Short Circuit
A. Remove both termination resistors from the CAN data link.
B. Disconnect the display panel.
C. Measure the resistance between the points that are listed in Table 2. Be sure to wiggle the wires in the harnesses as you make each resistance measurement.
Each check of the resistance indicates an open circuit.
Result: Each check of the resistance indicates an open circuit. The harness is not shorted. Proceed to Test Step 4.
Result: At least one check of the resistance does not indicate an open circuit.
There is a short circuit in a harness. There may be a problem with a connector. Repair the wiring and/or the connector. Replace part, if necessa