Cummins ISM Code 349 is the official Cummins fault code troubleshooting PDF that documents the auxiliary speed governor on ISM CM570 (1999-02) engines. This 2-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 | Auxiliary Speed Governor (DTCs) |
| Fault code | Code 349 · PID P191 · SPN FMI: 0/16 · FMI 0/16 |
| Warning lamp | Yellow |
| Year / Revision | Copyright 2017 |
| Pages | 2 |
| File size | 0.2 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 349 troubleshooting summary
The auxiliary speed governor provides a means to govern the engine independent of engine speed. This circuit controls output shafts or other devices downstream of a torque convertor. The auxiliary speed governor location varies with the OEM. The manual walks through 3 labelled troubleshooting steps that inspect connectors and pins, measure circuit resistance, and verify the fault code is inactive after the repair.
This fault can only be caused by a high-frequency input into the
auxiliary speed governor circuit.
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 349 manual
Heavy-duty diesel technicians, fleet service managers and independent workshop owners diagnosing a Code 349 on the auxiliary speed governor rely on this document to follow the manufacturer procedure instead of guessing at parts. Because Code 349 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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