P206AReductant Quality Sensor Circuit
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- The quality sensor sits in the DEF (AdBlue) tank, usually inside a module that also holds level and temperature elements, and estimates urea concentration, in GM's case by timing ultrasonic echoes. P206A is the general circuit code: the module cannot deliver a usable quality value, without a finer split into range, low or high. Deutz uses it with failure-type bytes: on the EMR L1 controller P206A-21 and P206A-22 mean the quality value left its valid range at the bottom or top, on EMR5 P206A-01 stands for erratic or incorrect data. FCA lists P206A for its 3.0L diesel trucks from model year 2016 among the codes that start the Service DEF countdown: the engine can no longer be restarted once 150 miles pass without repair. Without a trustworthy reading the controller cannot detect wrong fluid, which CARB requires.
- What you may notice
- MIL and DEF system warning
- Countdown to no-restart or speed limit
- DEF quality value missing in scan data
- Likely causes
- LikelyCorroded or loose connector at the tank sensor module
- PossibleFailed quality sensor or tank sensor module
- PossibleDamaged signal or supply wiring near the tank
- RareFrozen, aerated or heavily contaminated fluid around the sensor
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €100 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.