Cummins ISM Code 341 is the official Cummins fault code troubleshooting PDF that documents the unswitched battery supply circuit on ISM CM570 (1999-02) engines. This 4-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 | Unswitched Battery Supply Circuit (DTCs) |
| Fault code | Code 341 · PID S253 · SPN 630 · FMI 2/2 |
| Warning lamp | Yellow |
| Year / Revision | Copyright 2017 |
| Pages | 4 |
| 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 341 troubleshooting summary
The ECM receives constant voltage from the batteries through the unswitched battery wires that are connected directly to the positive (+) battery post. There are two in-line 15-amp fuses in the unswitched battery wires to protect the engine harness from overheating. The ECM is connected to the battery by the OEM harness. The manual walks through 10 labelled troubleshooting steps that inspect connectors and pins, measure circuit resistance, and verify the fault code is inactive after the repair.
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 341 manual
Heavy-duty diesel technicians, fleet service managers and independent workshop owners diagnosing a Code 341 on the unswitched battery supply circuit rely on this document to follow the manufacturer procedure instead of guessing at parts. Because Code 341 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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