Cummins ISM Code 235 documents the Engine Coolant Level Engine Protection diagnostic and troubleshooting procedure for the Cummins ISM CM570 (1999-02) engine platform. This 6-page fault code sheet from TruckFaultCodes.com (Copyright 2017) covers fault code 235 (PID P111, SPN 111, FMI 1/1, RED lamp) and the checks used to confirm and clear it.
Official document details
| Brand | Cummins |
|---|---|
| Model coverage | ISM CM570, ISX CM570, Signature CM570 (1999-02) |
| System / Group | Diagnostic Trouble Codes (DTCs) |
| Fault code | 235 — PID P111, SPN 111, FMI 1/1 |
| Warning lamp | RED |
| Pages | 6 |
| File size | 0.3 MB |
| Format | |
| Language | English |
Document table of contents
- Circuit description
- Component location
- Shop talk
- Troubleshooting steps
- Fault code verification and clearing
Cummins ISM Code 235 diagnostic steps
This engine-protection fault reports a low coolant level from the sensor in the radiator top tank or surge tank. Because the sensor is complex, a multimeter must not be used to test it. Technicians verify any shorting plug is wired correctly, inspect the harness between the Weather-Pack four-way connector and the sensor, and confirm the sensor sits mid-tank. A low level can trigger a progressive power or speed derate, or shutdown if the engine-protection shutdown feature is enabled.
Applicable truck models
This sheet applies to Cummins ISM CM570, ISX CM570, and Signature CM570 (1999-02) engines built around the CM570 ECM and the coolant level sensor. The coolant level sensor is an OEM-supplied part in the radiator top tank or surge tank. The document is laid out with a circuit description, a component location note, shop-talk tips, and a step-by-step troubleshooting chart whose go-to branches route the technician through each measurement. Refer to the official Cummins engine support site for wiring diagrams and component part numbers.
Who needs this Cummins ISM Code 235 manual
Heavy-duty diesel technicians, fleet service teams, and owner-operators diagnosing a red-lamp coolant level sensor fault will use this sheet to follow the factory decision tree, confirm the reading, and repair the harness, connector, or component instead of replacing parts on guesswork. It spells out each measurement threshold and its pass or fail branch, so the fault can be verified active, the repair validated, and the inactive code cleared with the diagnostic tool.
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