Cummins M11 code 151 is the Cummins M11 CELECT Plus diagnostic entry for fault code 151, coolant temperature engine protection (SPN 110, FMI 0). This page summarises what the code reports, the circuit involved, and the official Cummins troubleshooting document behind it, taken from the fault-code publication for Cummins M11 CELECT Plus engines. It is written for mechanics and workshop owners who want to confirm the code before ordering parts.
What Cummins M11 code 151 means
Fault code 151 is logged against coolant temperature engine protection. The document reports a diagnostic lamp. The coolant temperature sensor is used by the electronic control module (ECM) to monitor the temperature of the engine coolant. The coolant temperature is used by the ECM for the engine protection system, and the timing and fueling control.
Circuit description and component location
Component location. M11 – The coolant temperature sensor is located in the front of the thermostat housing support on most M11 applications. On bus applications, the sensor will usually be located at the rear on the thermostat housing support. N14 – The coolant temperature sensor is located on the top of the thermostat housing.
The official diagnostic identifiers for this fault let you match the code across scan tools and repair records:
- PID: P110
- SPN: 110
- FMI: 0
- Lamp: ENGINE
- SRT code: 00-014
The document walks the technician through the numbered troubleshooting steps for this circuit, from connector inspection to resistance and short-to-ground measurements, so the fault can be confirmed before any part is replaced. Each step ends in a yes or no branch that either clears the code or sends you to the next check, which keeps the diagnosis systematic and avoids guesswork on the bench.
How to diagnose Cummins M11 code 151
Start by reading the live codes with an approved Cummins diagnostic tool and confirming the code is active. Inspect the harness connector pins for bent or corroded terminals, pushed-back pins and moisture, then follow the manufacturer resistance and continuity checks in the order given. Diagnostic procedures for Cummins M11 CELECT Plus engines are published by Cummins; see the Cummins official website for engine documentation and authorised service-network support.
Official references and part numbers
Standard Repair Time reference SRT 00-014; Cummins Troubleshooting and Repair Manual, Bulletin 3666142. Use these identifiers to order the correct Cummins service publication and tooling, and to log the repair accurately for the fleet record. The full PDF is filed in the DiagTechPro manuals library for mechanics and workshop owners 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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