This coolant level sensor circuit guide covers Cummins Fault Code 422 (PID P111, SPN 111, FMI 2, SRT 00-610) on the M11 CELECT Plus. The 5-page yellow-lamp document explains how low coolant triggers a progressive power derate.
Official document details
| Brand | Cummins |
|---|---|
| Model coverage | M11 CELECT Plus (1995-98) |
| System / group | Coolant Level Sensor Circuit |
| Fault code | 422 |
| PID / SPN | P111 / SPN 111 |
| FMI | 2 |
| Diagnostic lamp | Yellow |
| SRT | 00-610 |
| Pages | 5 |
| File size | 0.3 MB |
| Format | |
| Language | English |
| Source | Cummins fault code reference (TruckFaultCodes.com, 2017) |
Document table of contents
- Circuit description
- Component location
- Shop talk diagnostic notes
- Step-by-step troubleshooting
- Fault verification and clearing codes
level sensor circuit checks
The sensor monitors coolant level in the cooling system and reports to the ECM through the sensor harness; the document calls it a very complex sensor and warns technicians not to check it with a multimeter. If the radiator coolant level drops below a set point, a progressive power derate with increasing time after the alert occurs. The sensor is OEM-controlled, so actual wiring can differ from the Robert Shaw sensor shown, and the manual tells the technician to consult the OEM for the pinouts on the OEM side of the 21-pin Deutsch connector. It is located in the radiator top tank or surge tank, and troubleshooting begins by confirming related codes are inactive.
Applicable truck models
Coverage is the Cummins M11 CELECT Plus (1995-98) with an OEM-supplied coolant level sensor. Confirm the OEM pinouts and derate behavior on the official Cummins website.
Who needs this level sensor circuit manual
Technicians diagnosing coolant-level warnings, power derates, or OEM sensor wiring on M11 CELECT Plus trucks use this chart and its multimeter warning.
The full PDF is available in the DiagTechPro manuals library; a free account is required to download.
Applies to these truck models
This is the manufacturer document shared across 2 model families. It applies to:
- Cummins DTCs
- Cummins M11 CELECT Plus (1995-98)
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