OBD-II code · Powertrain (generic, extended)
P20C9 Reductant Control Module Requested MIL Illumination
The dedicated reductant/SCR control module has requested that the master PCM illuminate the malfunction indicator lamp — a generic forward of an internal SCR fault. Read the SCR module subcodes for the actual cause.
Is it safe to drive with P20C9?
Usually safe for short trips, but don’t ignore it: the underlying fault can get more expensive over time.
Common causes
- Most likelyInternal SCR module fault — read subcodes
Symptoms
- Check engine light or NOx warning on
- AdBlue/DEF level or quality warning
- Possible no-start countdown after ignore period
- Failed emissions inspection (NOx)
Repair at a glance
- Difficulty
- Hard
- DIY friendly
- Best left to a mechanic
- Typical labour
- 0.5–6 h
- Emissions test
- Likely to fail
- Parts involved
- Scr Control Module
Related codes
- P20C6Reductant Heater D Control Circuit Performance
- P20C7Reductant Heater D Control Circuit Low
- P20C8Reductant Heater D Control Circuit High
- P20CAReductant Injection Air Pressure Leakage
- P20CBExhaust Aftertreatment Fuel Injector A Control Circuit/Open
- P20CCExhaust Aftertreatment Fuel Injector A Control Performance
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.