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TuningBot DTC Database · v4.37.14

P20EF SCR NOx Pre - Catalyst Efficiency Below Threshold Bank 1

Generic (OBD-II) interpretation in the TuningBot DTC database.

P · PowertrainEmissionsOBD2

What P20EF means

P20EF
SCR NOx Pre - Catalyst Efficiency Below Threshold Bank 1 Generic · emissions Data confidence 85%

The control module calculated that SCR NOx Pre - Catalyst efficiency dropped below the calibrated threshold for this application.

Symptoms

  • MIL or SCR/AdBlue warning illuminated
  • Possible start-count-down or torque limitation on some applications

Possible causes

  • Reductant quality or level fault
  • Dosing valve or supply module fault
  • NOx sensor fault
  • Frozen or crystallized reductant lines
  • Wiring or connector fault

Recommended checks

  • Read NOx sensor values and dosing system status
  • Check reductant level and quality data
  • Inspect dosing valve, lines and heater operation
  • Check wiring and connectors of the SCR components
  • Check for OEM technical bulletins and software updates

Related and nearby codes

P20 range
P2000P2001P2002P2003P2004P2005P2006P2007P2008P2009P200AP200BP200CP200DP200EP200FP2010P2011

How to read P20EF

P

Powertrain: engine, transmission and driveline systems.

2

Generic SAE-standard code: same meaning on every make.

0EF

Specific fault index within the subsystem.

Frequently asked questions about P20EF

What does P20EF mean?

SCR NOx Pre - Catalyst Efficiency Below Threshold Bank 1. The control module calculated that SCR NOx Pre - Catalyst efficiency dropped below the calibrated threshold for this application.

Is P20EF generic or manufacturer-specific?

P20EF is a generic OBD-II code: it has the same meaning on every make and model that follows the SAE standard.

Can TuningBot remove P20EF at file level?

If the fault logic lives in the ECU calibration, yes: our DTC Removal file service disables the specific fault entry and, where the ECU needs it, corrects the checksum too. Not sure whether your case qualifies? Request a free assessment and our engineers will check your ECU file.

Other file services

Stage 1/2/3 TuningDPF RemovalEGR RemovalAdBlue / SCR RemovalDTC RemovalIMMO OFFSpeed Limiter (Vmax)

Understand the system behind this code: SCR / AdBlue System

ECU tuningDyno-tested results by model and engine See the results →

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