SEAL-O-RING 1522938 - Caterpillar

Self-Diagnostics
The electronic control system has the ability to detect problems. When a problem is detected, a diagnostic trouble code is generated. In most cases, the code is also logged in the Electronic Control Module (ECM).When codes occur, the codes are active. Active codes indicate that a problem of some kind currently exists. Always troubleshoot active codes before any other work is performed. If an engine has an active code, find the code in this manual and proceed to diagnose the cause of the code.Diagnostic codes that are stored in the ECM are logged. Logged codes do not necessarily indicate that something needs to be repaired. The problem may have been temporary, or the problem may have been repaired since the problem was logged. Logged codes may result from intermittent problems.Refer to Troubleshooting, "Diagnostic Trouble Codes" for a complete list of the codes that apply to these engines.