SCR NOx Catalyst Efficiency
What does MAXXFORCE-P20EE-13 mean?
The MAXXFORCE-P20EE-13 (MaxxForce) diesel fault code means: SCR NOx Catalyst Efficiency. This is a serious severity code.
Common Symptoms
- CEL
- Countdown to derate
- Poor MPG
Probable Causes (Ranked by Likelihood)
- DEF quality poor Likely
- Failed NOx sensors Likely
- SCR catalyst thermal damage Possible
Step-by-Step Diagnostic Procedure
Refractometer-test DEF.
Replace NOx sensors before SCR.
MaxxForce 13 was late to add SCR (2013+).
Frequently Asked Questions
What is P20EE on a MaxxForce 13 (12.4L)?
P20EE on a MaxxForce 13 (12.4L) (2008-2014) indicates: SCR NOx Catalyst Efficiency. This is a known fault code on the MaxxForce engine family and typically points to the causes listed above.
Can I drive with P20EE on my MaxxForce?
Only drive short distances to reach a repair facility. Continued operation may cause further damage or progressive derate.
How much does it cost to fix MaxxForce P20EE?
Repair cost is typically $600-$7,000 depending on the underlying cause and shop rate. Many MaxxForce faults (especially EGR cooler, head bolt, and VGT repairs) are major expenses that drove fleet owners to repower with Cummins or retire these trucks early.