P206A
PPowertrainReductant (AdBlue) Quality Sensor Circuit
What does this code mean?
Severity : MediumP206A points to a fault in the reductant quality sensor circuit, meaning the AdBlue or DEF quality sensor. This sensor sits in the tank and checks fluid concentration so the SCR system can reduce NOx emissions properly. The control module is no longer receiving a usable signal from it.
Symptoms
- Check engine or AdBlue warning light on.
- Emissions system warning message.
- Countdown before start restriction on some vehicles.
- Possible reduced power.
Possible causes
- Faulty AdBlue quality sensor, often built into the tank module.
- Corroded connector or damaged wiring.
- Crystallised or contaminated AdBlue.
- Sensor power supply fault.
- SCR control module fault, which is rare.
Diagnosis and repair
- Inspect the AdBlue tank module connector and wiring.
- Check AdBlue quality with a refractometer.
- Measure sensor supply and ground with a multimeter.
- Drain and refill with compliant AdBlue if the fluid is contaminated.
- Replace the sensor or module if needed, clear the code and road test.
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Code
P206A
Category
Powertrain
Prefix
P
Standard
OBD-II / SAE J2012