This Cummins 3543 troubleshooting document explains Fault Code 3543 for NOx limits exceeded due to insufficient reagent quality. It covers SCR conversion checks, DEF quality inspection, dosing system tests, exhaust leak checks, stationary regeneration, ECM calibration review, and fault clearing with INSITE™ electronic service tool.
Official Cummins 3543 troubleshooting document details
| Brand | Cummins |
|---|---|
| Model coverage | ISB6.7 CM2250, ISC8.3 and ISL9 CM2250, ISX15 CM2250, ISX11.9 CM2250 |
| System/Group | ISB6.7 CM2250 (2010-12) / DTCs; NOx Sensor; SCR and DEF aftertreatment diagnostics |
| Publication no. | Not specified for this PDF; associated bulletin numbers include 4022254, 4022257, 4022250, and 2883445 |
| Year/Revision | Year unknown; last modified entries shown as 31-Dec-2010 and 16-Nov-2010 |
| Pages | 15 |
| File size | 0.2 MB |
| Format | |
| Language | English |
Document table of contents
- Overview
- Circuit Description
- Component Location
- Conditions for Running the Diagnostics
- FAULT CODE 3543 – NOx Limits Exceeded Due to Insufficient Reagent Quality – Condition Exists
- Conditions for Setting the Fault Codes
- Action Taken When the Fault Code is Active
- Conditions for Clearing the Fault Code
- Shop Talk
- Associated Procedures
- Troubleshooting Steps
- Guided Step 1 – Check for active fault codes relating to the DEF dosing system
- Guided Step 2B – Check the diesel exhaust fluid quality
- Guided Step 3 – Check the aftertreatment system
- Guided Step 3A – Check the exhaust system for leaks
- Guided Step 4B – Check for active fault codes
- Guided Step 4C – Check for active fault codes
- Guided Step 5B – Disable the fault code
Applicable truck models
This file applies to Cummins CM2250 engine platforms identified in the extract: ISB6.7 CM2250, ISC8.3 and ISL9 CM2250, ISX15 CM2250, and ISX11.9 CM2250. The diagnostic is for an aftertreatment system using a diesel exhaust fluid tank, SCR catalyst, aftertreatment intake NOx sensor, aftertreatment outlet NOx sensor, diesel exhaust fluid dosing unit, dosing valve, dosing unit filter, decomposition tube, and ECM monitoring. For manufacturer information, visit Cummins official website.
Who needs this Cummins 3543 troubleshooting manual
Workshop owners, diesel technicians, and fleet mechanics need this Cummins 3543 troubleshooting manual when a CM2250 engine logs SPN 4094 FMI 31 and the amber CHECK ENGINE lamp or MIL is active. The procedure helps confirm DEF contamination, dosing faults, exhaust leaks, DEF deposits, SCR catalyst concerns, and required INSITE™ actions before clearing the code.
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