DISC ASSEMBLY 7D8224 - Caterpillar

Table 1
Code and Description Conditions which Generate this Code Conditions which Generate this Code
1632-9 Backup Engine Control Module abnormal update rate Communication with the backup Electronic Control Module (ECM) cannot be established within three seconds after the Primary ECM is powered up. After communication with the backup ECM has been established, communication stops for one second. The ECM will log the diagnostic code. The backup ECM will not be available for engine control. Note: This procedure checks for an open circuit or for a short circuit in the Cat Data Link. If you are experiencing problems with communications between the Cat® Electronic Technician (ET) and the Electronic Control Module (ECM), refer to Troubleshooting, "Electronic Service Tool Does Not Communicate", before you use this procedure.The Cat Data Link is the standard data link that is used by the ECM to communicate with Cat ET. The ECM communicates with Cat ET to share status information and diagnostic information. Cat ET can also be used to configure the ECM parameters. This information will not be available if communication fails between the ECM and Cat ET.
Illustration 1 g01390276
Schematic for the Cat Data Link
Table 2
Troubleshooting Test Steps Values Results
1. Inspect the Electrical Connectors and the Wiring
A. Remove electrical power from the ECM.
B. Thoroughly inspect connectors. Refer to Troubleshooting, "Electrical Connectors - Inspect".
C. Perform a 45 N (10 lb) pull test on each of the wires that are associated with the Cat Data Link.
D. Check the allen head screw on each ECM connector for the proper torque. Also, check the allen head screw on the customer connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect", for the correct torque values.
Connectors, Pins, and Sockets
Result: The harness and the connectors appear to be OK.
Proceed to Test Step 2.
Result: The connectors and/or the wiring are not OK.
Repair: 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 original problem is resolved.
STOP
Table 3
Resistance Measurements for the Cat Data Link
Connector and Terminal Terminal
P1-8 (Cat Data Link +) All the other terminals on the P1 connector
Negative ground
P1-9 (Cat Data Link -) All the other terminals on the P1 connector
Negative ground
Table 4
Troubleshooting Test Steps Values Results
2. Check for a Short Circuit
A. Disconnect the P1 ECM connector.
B. Disconnect Cat ET from