Cummins ISM Code 319 is the official Cummins fault code troubleshooting PDF that documents the real-time clock power circuit on ISM CM570 (1999-02) engines. This 6-page reference from the Cummins service literature explains the circuit, the likely causes behind the yellow warning lamp, and the step-by-step checks a technician follows to confirm the repair.
Official document details
| Brand | Cummins |
|---|---|
| Model coverage | ISM CM570, ISX CM570 and Signature CM570 (1999-02) |
| System / Group | Real-Time Clock Power Circuit (DTCs) |
| Fault code | Code 319 · PID P251 · SPN 251 · FMI 2/2 |
| Warning lamp | Maintenance |
| Year / Revision | Copyright 2017 |
| Pages | 6 |
| File size | 0.3 MB |
| Format | |
| Language | English |
Document table of contents
- Circuit description
- Component location
- Shop talk – possible causes
- Troubleshooting steps
- Fault code verification and clearing
Cummins ISM Code 319 troubleshooting summary
Under ordinary operating conditions, the real-time clock in the ECM is powered by the vehicle’s batteries. If battery power to the ECM is lost, then the real-time clock will be powered by a battery backup module (if equipped). The real-time clock battery backup module is secured to the wiring harness in the vicinity of the ECM. The manual walks through 8 labelled troubleshooting steps that inspect connectors and pins, measure circuit resistance, and verify the fault code is inactive after the repair.
Possible causes listed in the Shop Talk section include:
- A weak or failed battery backup module
- Failed wiring or connectors between the battery backup
- The engine is not equipped with a battery backup module,
Referenced Cummins service tools and part numbers: 3824510.
Applicable truck models
This procedure applies to Cummins ISM CM570, ISX CM570 and Signature CM570 engines built in the 1999-02 range, as used in Class 8 highway trucks. Always confirm the exact engine dataplate before servicing. Full engine specifications and dealer support are available on the Cummins official website.
Who needs this Cummins ISM Code 319 manual
Heavy-duty diesel technicians, fleet service managers and independent workshop owners diagnosing a Code 319 on the real-time clock power circuit rely on this document to follow the manufacturer procedure instead of guessing at parts. Because Code 319 shares its troubleshooting logic with the ISX CM570 and Signature CM570 platforms, a single PDF supports several Cummins engine families in the same workshop.
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