P20EA — Reductant Quality Deviation
What it means: Reductant Quality Deviation.
How serious / can you keep driving: Critical. Stop as soon as it's safe.
Check first: Test DEF with refractometer (should read 32.5%)
Don't risk it — look up listed providers near you and give them this code when you call.
Listed providers nearest Indianapolis, IN
Closest first. Tell them P20EA and what the truck is doing. RoadService.app lists these providers and does not employ them or carry out the repair.
- 0.0 mi away — based in Indianapolis, IN · (317) 789-5002
- 0.0 mi away — based in Indianapolis, IN · (317) 300-7000
- 0.0 mi away — based in Indianapolis, IN · (317) 646-8208
Seen on: Heavy Truck/Diesel
What P20EA means
Reductant Quality Deviation. Common causes: DEF quality out of specification.
How serious is it?
Critical. Stop as soon as it's safe.
Most likely causes
- DEF quality out of specification
- Wrong fluid
- diluted DEF
- freezing/thawing contamination
First moves (roadside)
- Test DEF with refractometer (should read 32.5%)
- drain and refill with fresh DEF
FAQ
Reductant Quality Deviation. Common causes: DEF quality out of specification.
Critical — Stop as soon as it's safe.
The most common cause is: DEF quality out of specification. Other possibilities include Wrong fluid; diluted DEF; freezing/thawing contamination.
Stop as soon as it's safe. When in doubt, get a qualified mobile diesel tech on the truck before continuing.
Related codes
Codes that commonly appear alongside P20EA, or share the same subsystem.
- SCR Operator Inducement — Severe Derate Active (SPN 5246 FMI 0)
- Aftertreatment 1 Diesel Particulate Filter Differential Pressure - Data Valid But Above Normal Operating Range, Most Severe Level (DPF severely restricted / plugged) (SPN 3251 FMI 0)
- Aftertreatment 1 Diesel Exhaust Fluid Quality - Data Valid But Below Normal Operating Range, Most Severe Level (DEF quality/concentration incorrect) (SPN 4364 FMI 1)
- DPF Differential Pressure — Data Erratic (SPN 3251 FMI 2)
- DEF Dosing Unit — Not Responding Properly (SPN 3361 FMI 7)
- SCR Conversion Efficiency — Below Threshold (SPN 4364 FMI 18)
- DEF Quality — Out of Spec (SPN 4094 FMI 31)
- EGR Temperature — Too High (SPN 412 FMI 0)
Same symptom: DEF / SCR fault
Other codes in the DEF and SCR chain — the ones that end in an inducement countdown.
- Reductant System Performance Bank 1 (P204F) · Aftertreatment & Emissions
- DEF tank level low (SPN 1761 FMI 18) · Aftertreatment & Emissions
- DEF tank temp sensor — voltage high (SPN 3031 FMI 3) · Aftertreatment & Emissions
- Upstream NOx sensor — internal failure reported (SPN 3216 FMI 12) · Aftertreatment & Emissions
- SCR inlet NOx sensor — erratic (SPN 3216 FMI 2) · Aftertreatment & Emissions
- Upstream NOx sensor — abnormal update rate (SPN 3216 FMI 9) · Aftertreatment & Emissions
Find a mechanic or related guides
General diagnostic guidance for diesel engines (Cummins, Detroit, PACCAR, Volvo, Mack and more). Not a substitute for a scan-tool diagnosis on your specific truck.