TRANSMISSION G 0338019 - Caterpillar

Table 3
Transmission/Chassis ECM (MID 27)
DTC Code Description System Response
248-9 Cat Data Link - Abnormal Update Rate Communication across the data link will be interrupted. Some machine functions will be disabled.
296-9 Transmission Control - Abnormal Update Rate Communication between the Transmission ECM and other ECM modules will be interrupted.
590-9 Engine Control Module - Abnormal Update Rate Communication between the Transmission ECM and the Engine ECM modules will be interrupted.
596-9 Implement Control - Abnormal Update Rate Communication between the Transmission ECM and the Implement ECM modules will be interrupted.
1421-9 Rear Engine Control Module - Abnormal Update Rate Communication between the Transmission ECM and the Rear Engine Control ECM modules will be interrupted. Each Cat Data Link circuit is an input and output of select electronic control modules. The data link is designed to carry communications between the electronic control modules. The data link is not a visible component. The data link consists of internal control circuits and the connecting harness wiring.Possible Causes and Schematics
The diagnostic code is caused by abnormal communications between specific ECM modules via the Cat Data Link. The update rate is not correct. If a diagnostic code is present, correct the related diagnostic code.The DTC 248-9 is used as a companion code and indicates a J1939 data-link problem. This DTC indicates that a specific ECM has lost all communication with another ECM. Note: The 248-9 DTC will never be activated as a stand-alone diagnostic code.Possible causes for an FMI 9 failure mode code are:
A fuse for one of the ECM modules may have failed.
The software is incorrect or incompatible for one of the modules within the data link.
The machine harness has failed.
One of the ECM modules in the data link has failed.The DTC is recorded when Cat® Electronic Technician (Cat ET) does not receive the expected information from the ECM associated with the DTC. The information is communicated over the Cat data link.
Illustration 1 g03348367
CAT Data Link circuit connections for 621K, 623K, and 627K Wheel Tractor Scrapers
Note: The diagram above is simplified schematic of the Cat data link connections. The schematic is electrically correct. However, not all of the possible harness connectors are shown. Refer to the latest revision of the Electrical Schematic for your specific machine. Refer to the list below to identify the correct schematic for your machine.
Electrical Schematic, UENR2689 for the 621K Tractor/Scraper.
Electrical Schematic, UENR2690 for the 623K Tractor/Scraper.
Electrical Schematic, UENR2691 for the 627K Tractor/Scraper.Troubleshooting Procedure
Prior to beginning this procedure, inspect the harness connectors that are involved in this circuit. Poor connections can often be the cause of a problem in an electrical circuit. Verify that all connections in the circuit are clean, secure, and in good condition. Check the wiring for pinch points or abrasions. Look for and repair areas that indicate wires are exposed. If a problem with a connection is found, correct the problem and verify that this diagnostic code is active before performing a troubleshooting procedure.
Table 4
Troubleshooting Test Steps Values Results
1. Identify The Active DTC Code Associated With The Cat Data