880816 Mercury CLAMP

Table 1
Diagnostic Trouble Codes for CAN Data Link
J1939 Code Code Description Comments
639-9 J1939 Network #1 : Abnormal Update Rate Another controller has incorrectly stopped transmitting data or another controller has incorrectly started transmitting data.
The ECM will log the diagnostic code.
The engine will not start.
Follow the troubleshooting procedure to identify the root cause of the fault. Note: Refer to Troubleshooting, "Sensors and Electrical Connectors"for the locations of the components listed in this procedure.The following background information is related to this procedure:The CAN data link is also known as the J1939 data links. A data link is an industry standard for sending data between different devices in the same application.High speed data is transferred via the data link. The data link cannot be accurately tested without complicated equipment. The data link requires a resistance of 60 Ohms between the two wires to transmit the data correctly. This resistance is made up of two 120 Ohm resistors. The two resistors are known as "Terminating Resistors". The terminating resistors should be at opposite ends of a data link circuit. If this resistance is not present, then the data will be intermittent or unreadable.Note: The wiring for a J1939 data link is a shielded twisted pair cable. If the wiring is damaged, the replacement type must be shielded twisted pair cable.
Illustration 1 g06108329
Schematic for the CAN data link
Table 2
Troubleshooting Test Steps Values Results
1. Inspect Electrical Connectors and Wiring
A. Turn the isolator switch to the OFF position.
B. Inspect the connectors in the circuit for 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 screw for the ECM connectors for correct torque of 6 N m (53 lb in).
E. Check all the wiring associated with the CAN data link for abrasions and pinch points.
Connector and/or wiring Result: The connector and/or wiring is NOT OK.
Repair: Repair the damaged wire or the damaged connector.
Use the electronic service tool to clear all logged diagnostic codes. Verify that the repair eliminates the fault.
Result: A damaged wire or damaged connector was not found.
Proceed to Test Step 2.
2. Check the Data Link Terminating Resistance
A. Disconnect the P1 connector from the ECM.
B. Measure the resistance between J1:46 and J1:47.
Between 50 Ohms and 70 Ohms
Result: The resistance is less than 50 Ohms - there is a short circuit in the harness.
Repair: Repair the connectors or the harness and/or replace the connectors or the harness. Ensure that all the seals are correctly in place and ensure that the connectors are correctly connected.
Use the electronic service tool to clear all logged diagnostic codes and then verify that the repair eliminates the fault.
Result: The resistance is between 110 and 130 Ohms - one of the terminating resistors may have failed.
Repair: Locate the two terminating resistors and remove the two terminating resistors from the harness. Depending on the application, one or both of the terminating resistors may be located in other ECMs on the data link.
Measure the resistance of the two terminating resistors.
If one of the terminating resistors is incorrect, replace the faulty terminating resistor.
If the two terminating resistors are between 110 and 130 Ohms, proceed to Test Step 4.
Result: The resistance is greater than 150 Ohms.
Proceed to Test Step 3.
Result: The resistance is between 50 and 70 Ohms. The resistance is OK.
The fault may be in the connection to other devices on the data link.
Proceed to Test Step 3.
3. Check the Data Link Wiring
A. Disconnect each of the connectors that connect other devices on the data link.
B. Use a multimeter to measure the resistance between P1:46 and the associated CAN+ pin on the control panel.
C. Use a multimeter to measure the resistance between P1:46 and pin (G) on the diagnostic connector.
E. Use a multimeter to measure the resistance between P1:47 and the associated CAN- pin on the control panel.
F. Use a multimeter to measure the resistance between P1:47 and pin (F) on the diagnostic connector.
Less than two Ohms
Result: At least one of the resistance measurements is greater than two Ohms - there is an open circuit or high resistance in the wiring.
Repair: Repair the connectors or the harness and/or replace the connectors or the harness.
Ensure that all seals are correctly in place and ensure that the connectors are correctly connected.
Use the electronic service tool to clear all logged diagnostic codes and then verify that the repair has eliminated the fault.
Result: All measured resistances are less than two Ohms.
Proceed to Test Step 4
4. Check the Other Devices on the CAN Data Link
A. Use the appropriate service tools to diagnose other devices on the data link.
Other CAN components
Result: At least one of the other devices is not operating correctly.
Repair:Use the appropriate service tools to repair other devices on the data link.
Use the electronic service tool to clear all logged diagnostic codes and then verify that the repair eliminates the fault.
Result: The other devices are operating correctly.
Repair: Contact the Technical Communicator at a Cat dealer.