Powertrain, generic (extended)

P20FE Reductant Metering Unit 1 Performance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

P20FE judges whether the first reductant metering unit actually delivers the quantity the SCR control asks for. GM's 2025 Duramax tables average a delivery compensation factor and set the code, Type A after one trip, once that factor passes 1.44, meaning the expected pressure drop no longer proves correct dosing. VW Group uses it on 3.0 TDI models: Porsche reflashed 2015–2016 Cayenne Diesel because the check was too sensitive in the cold; Audi tied it on 2012–2015 Q7 to a loose filter housing letting unfiltered AdBlue damage the pressure sensor and pump; VW's 2015 Touareg tip first checks the injector part number, then runs the metering quantity test. GM also updated software for it (23-NA-193, 24-NA-058). Unit 2 is P2EAD.

Likely causes

Partly blocked or crystallised dosing injector
Loose or damaged tank filter letting debris reach pump and sensor
Over-sensitive diagnostic calibration (software update available)
Air in the dosing lines after service or low fluid level

Symptoms

  • Malfunction indicator lamp on
  • AdBlue/DEF system warning in the cluster
  • Higher NOx, possible SCR efficiency codes (P20EE)

Repair estimate

DifficultyHardWorkshop job
Parts and labour€100–1,800
Time0.5–5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

reductant metering unit

Related codes

P2EADP20F4P20E9P20EE

References: gsi.ext.gm.com, static.nhtsa.gov, static.nhtsa.gov, static.nhtsa.gov.