Aftertreatment SCR Outlet NOx Sensor - Data Erratic
What does CUMMINS-2614 mean?
The CUMMINS-2614 (Cummins) diesel fault code means: Aftertreatment SCR Outlet NOx Sensor - Data Erratic. This is a moderate severity code.
Common Symptoms
- NOx sensor fault lamp on dash
- Engine derate after warning period
- Increased DEF dosing to compensate
- Aftertreatment efficiency warnings
- Failed emissions testing (CARB/EPA)
- SCR catalyst efficiency message on dash
Probable Causes (Ranked by Likelihood)
- Failed NOx sensor (typical 150K-300K mile life) Very Likely
- Corroded NOx sensor harness or connector Likely
- NOx sensor contamination from DEF crystallization Likely
- SCR catalyst aged or damaged by overheat Possible
- Exhaust leak upstream of sensor Possible
- ECM or ACM calibration out of date Less Likely
Step-by-Step Diagnostic Procedure
Connect INSITE and monitor both inlet and outlet NOx sensor live readings to identify the faulty sensor for 2614.
Inspect NOx sensor harness routing for damage from exhaust heat, chafing, or crystallized DEF contamination.
Measure NOx sensor heater circuit resistance and supply voltage at the module connector.
If sensor is more than 200,000 miles old with this fault, replacement is typically required -- NOx sensors have a finite service life.
Check SCR catalyst efficiency via INSITE active test; a failed SCR can mimic NOx sensor faults.
Verify exhaust leaks upstream of the sensor are repaired, as a leak will skew readings and trigger this code.
Common Fixes by Vehicle
What techs usually find when diagnosing CUMMINS-2614 on specific diesel vehicles:
FC 2614 (NOx sensor bank 2 / outlet / downstream SCR) almost always requires sensor replacement -- these are not rebuildable. The outlet sensor sits past the SCR catalyst in the exhaust. Expect $300-$500 for the sensor and another $150-$300 labor at a shop. DIY is achievable with a 22mm O2 socket and anti-seize, but the sensor must match the truck's emissions calibration -- use OEM Cummins or Bosch.
On X15/ISX15 trucks, 2614 outlet NOx faults are often caused by soot contamination rather than a true sensor failure -- a DPF that is overdue for service can coat the NOx sensor tip. Before replacing, pull the DPF ash load data; if it's above 75%, clean or replace the DPF first. If DPF is healthy, replace the sensor. New OEM NOx sensors are $600-$900 for heavy-duty applications.
Frequently Asked Questions
What is Cummins fault code 2614?
Cummins fault code 2614 indicates: Aftertreatment SCR Outlet NOx Sensor - Data Erratic. It is a moderate-severity fault in the aftertreatment or emissions system.
Can I drive with Cummins fault code 2614?
Short-term, yes, but the engine will enter derate (typically starting at 55 mph and progressing to 5 mph for emissions faults). Drive directly to a repair facility. Do not defer this fault more than a few operating hours.
How much does it cost to fix Cummins fault 2614?
Repair cost is approximately $800-$2,500 including parts, labor, and any dealer programming required. DIY repairs (sensor replacement) fall at the low end; pump, aftertreatment, or ECM work falls at the high end and usually requires INSITE diagnostic software.