BLOCK (front) 9K2744 - Caterpillar

Table 1
Diagnostic Codes Table    
Code and Description    Conditions which Generate this Code    System Response    
296-9 Transmission Control abnormal update rate     Communication with the transmission control cannot be established within three seconds after the Electronic Control Module (ECM) is powered up. After communication with the transmission control has been established, communication stops for one second.     The ECM will log the diagnostic code. All features of the transmission control that rely on the data link are disabled. The ECM will disable the automatic control of engine speed through the throttle lock feature.    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 Caterpillar Electronic Technician (ET) and the 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 in order to share status information and diagnostic information. Cat ET can also be used to configure the ECM parameters.
Illustration 1 g01340327
Typical schematic for the Cat Data LinkTest Step 1. Inspect the Electrical Connectors and the Wiring
Remove electrical power from the ECM.
Illustration 2 g01340344
Locations of the connectors for the Cat Data Link (typical left side engine view) (1) J1/P1 ECM connectors (2) Machine interface connectors (20-Pin)
Thoroughly inspect connectors (1) and (2). Refer to Troubleshooting, "Electrical Connectors - Inspect".
Illustration 3 g01312112
Terminal locations at the P1 ECM connector for the Cat Data Link (P1-8) Cat Data Link + (P1-9) Cat Data Link −
Illustration 4 g01340345
Terminal locations at the machine interface connector (20-Pin) for the Cat Data Link (Terminal 14) Cat Data Link + (Terminal 15) Cat Data Link −
Perform a 45 N (10 lb) pull test on each of the wires that are associated with the Cat Data Link.
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.Expected Result:All connectors, pins, and sockets are completely inserted and coupled. The harness and wiring are free of corrosion, of abrasion, and of pinch points.Results:
OK - The harness and the connectors appear to be OK. Proceed to Test Step 2.
Not OK - 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.STOPTest Step 2. Check for a Short Circuit
Disconnect the P1 ECM connector.
Disconnect Cat ET from the service tool connector.
Disconnect any other control modules from the Cat Data Link. Refer to the electrical schematic in order to identify other control modules on the Cat Data Link.
Measure the resistance between the points that are listed in Table 2. Be sure to wiggle the wires in the harnesses