The following is a list of codes that are associated with the Cat® Data Link of the machine.
| Theft Deterrent Module ECM (MID 436) | ||
|---|---|---|
| DTC | Code Description | System Response |
| 248-12 | Cat Data Link malfunction | The service tool cannot detect the ECM.
Communication failures are indicated by another ECM. |
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.
This diagnostic code is recorded when the ECM cannot send information, or the ECM does not receive expected information from the data link (wire 892-BR(Brown)and wire 893-GN(Green)or wire 944-OR(Orange)and wire 945-BR(Brown)).
The diagnostic code is caused by abnormal communications between the ECM and a specific ECM module via the Data Link. If a diagnostic code is present, correct the related diagnostic code.
Possible causes for an FMI 12 diagnostic code are:
- There is an open circuit or a short circuit on the data link.
- There is a failure of the hardware for data link.
The 248-9 DTC is used by the ECM as a companion code and indicates a Cat Data Link problem. This DTC indicates that the ECM has lost all communication with another ECM. This companion code is simultaneously activated with the 590-9 DTC.
Note: The 248-9 DTC will never be activated by the ECM as a stand-alone diagnostic code.
Note: The locations of the components of the MSS will vary between machines. If the MSS was installed by a Caterpillar dealer, consult the installation instructions for component locations. If the MSS was an attachment that was installed at the factory, consult the electrical schematic for that machine.
Diagnostic Trouble Code Procedure
Note: 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.
- Identify the active FMI code associated with the components.
- Determine which code is present and use the list below to determine which procedure to follow.
- FMI 12 diagnostic code, proceed to Table 2.
| FMI 12 Troubleshooting | ||
|---|---|---|
| Troubleshooting Test Steps | Values | Results |
| 1. CLEAR THE DIAGNOSTIC CODES A. Use the ET to clear the logged diagnostic codes. B. Use a valid electronic key to start the machine. Determine if CID 0248 FMI 12 is present. |
CID 0248 FMI 12 is present. |
OK - CID 0248 FMI 12 is present. The problem was not caused by the use of an invalid electronic key. Proceed to Test Step 2. NOT OK - CID 0248 FMI 12 is NOT present. The problem was caused by the use of an invalid key in the key start switch. STOP. |
| 2. INSPECT THE HARNESS CONNECTORS A. Inspect the connections for the machine harness that are related to the data link. B. Make sure that connectors are clean and tight. C.If necessary, repair the machine harness or replace the machine harness. D. Use the ET to clear the diagnostic codes. E. Use a valid electronic key to start the machine. F. Determine if CID 0248 FMI 12 is present. |
CID 0248 FMI 12 is present. |
OK - The diagnostic code is present. Proceed to Test Step 3. NOT OK -The diagnostic code no longer exists and a machine harness connector was faulty. The failure is not present now. An intermittent connection may exist in the data link circuits of the machine harness. Repair: Replace any connectors that do not have a tight fitting. Repair any wiring in the harness that appears to be damaged. Watch for a recurrence of this fault. STOP. |
| 3. CHECK FOR A SHORTED HARNESS A. Turn the battery disconnect switch to the OFF position. B. Disconnect the connector for the machine wiring harness from the MSS3s ECM. Disconnect the Cat Data Link from all other electronic control modules. C. At the connector for the MSS3s ECM, measure the resistance between contact 42 (wire 892-BR(Brown)or wire 944-OR(Orange)) and contact45 (wire 893-GN(Green)or wire 945-BR(Brown)). |
The resistance is greater than 5000 Ohms. |
OK - The resistance is greater than 5000 Ohms (no continuity). Harness circuit resistance is correct. Proceed to Test Step 4. NOT OK - Resistance is less than 5000 Ohms (continuity). The machine harness has failed. There is a short in the machine harness. Repair: Repair or replace the machine harness. Note: A resistance that is greater than 5 Ω but less than 5K Ω would indicate a loose connection or a corroded connection in the circuit. A resistance measurement that is greater than 5K Ω would indicate an open in the circuit. STOP. |
| 4. CHECK FOR AN OPEN HARNESS A. The disconnect switch remains OFF. B. The MSS3s ECM will remain disconnected from the machine harness. a. Locate the connector for the machine harness at the MSS3s ECM. Place a jumper wire between contact 1 (wire 892-BR(Brown)or wire 944-OR(Orange)) and 3 (wire 893-GN(Green)or wire 945-BR(Brown)). b. Locate the machine harness connector of another ECM. Check for continuity in the wiring for the Cat Data Link at the ECM. The pin numbers and the wires will vary between electronic control modules. Each ECM must be checked individually. |
There is continuity in the data link wiring. |
OK - There is continuity in the data link wiring. This circuit is not the cause of the fault. The ECM is possibly bad. Repair: If more than one ECM is reporting this fault code, the ECM is unlikely to be bad. If only one ECM has this fault, replace that ECM. Note: Prior to replacing the ECM, always contact the Technical Communicator at your dealership for possible consultation with Caterpillar. This consultation may effect repair time. Follow the steps in Troubleshooting, "ECM - Replace" if the ECM needs to be replaced. STOP. NOT OK - There is NO continuity in the data link wiring. The machine harness is faulty. The data link circuit is open in the machine harness. Repair: Repair or replace the machine harness. STOP. |