Cummins Diagnostic Fault Codes QSB QSC QSL QSM11 QSX15 QSK19 QSK23 QST30 QSK45 QSK60 QSK78

About this manual

This document provides a comprehensive list of diagnostic fault codes applicable to various Cummins engine models, including the QSB T2, QSC T2, QSL T2, QSM11, QSX15, QSK19, QSK23, QST30, and QSK45/60/78 series. It serves as a reference for identifying engine issues based on fault codes, lamp colors, and severity levels.

The guide categorizes faults by severity, ranging from Level 1 (Stop Engine Now – Damage Imminent) to Level 4 (Information Only). For each fault code, the document details the specific circuit or component involved, such as sensor circuits, actuators, and valves, along with the required action to be taken by the operator or technician.

What's inside

• Fault Severity Levels
• Engine Control Module Faults
• Sensor Circuit Faults
• Fuel System Faults
• Coolant and Oil System Faults
• Actuator and Valve Faults
• Engine Speed and Position Faults
• Vehicle Speed Sensor Faults

Specifications

Frequently asked questions

What engine models does this diagnostic fault code list apply to?

This list applies to Cummins engines including the QSB T2, QSC T2, QSL T2, QSM11, QSX15, QSK19, QSK23, QST30, and QSK45/60/78 models.

What action is required for a Fault Severity Level 1 code?

For a Level 1 fault, the operator must stop the engine immediately because damage is imminent.

When must an engine with a Fault Severity Level 2 code be repaired?

An engine with a Level 2 fault may continue to run but must be repaired the same day.