Reductant Quality Sensor
Measures the concentration of the urea solution, because the vehicle is not permitted to assume it has been given the right fluid. Reductant must be 32.5% urea in demineralised water — precisely, not approximately; weaker fluid cannot convert the nitrogen oxides the dosing calculation assumes it will.
It works indirectly, usually by timing an ultrasonic pulse through the fluid or measuring its electrical permittivity, both of which vary predictably with urea content. It normally shares a housing with the level and temperature sensors.
The distinction that matters when reading its codes: a circuit fault says the vehicle cannot check the fluid; a performance fault says the fluid has been checked and is wrong. Only the second is a reason to drain a tank, and confusing the two is an expensive mistake. Fluid ages — reductant degrades in heat and sunlight and has a genuine shelf life, so a part-used drum that stood through a summer can fail a quality check while the sensor is perfect.
Also known as: adblue quality sensor, def quality sensor, urea concentration sensor, scr quality sensor
Referenced by 16 codes
Codes involving this component (16)
- P207F Reductant Quality Performance High
- P206D Reductant Quality Sensor Circuit High Moderate
- U05A3 Invalid Data Received From Reductant Quality Module Moderate
- P206A Reductant Quality Sensor Circuit
- P206B Reductant Quality Sensor Circuit Range/Performance
- P206C Reductant Quality Sensor Circuit Low
- P21CD Reductant Quality Module Supply Voltage Low
- P21CE Reductant Quality Module Performance
- P24CB Reductant Tank Cap Switch Circuit
- P24CC Reductant Tank Cap Switch Circuit Range/Performance
- P24CD Reductant Tank Cap Switch Circuit Low
- P24CE Reductant Tank Cap Switch Circuit High
- P24CF Reductant Tank Cap Switch Circuit Intermittent/Erratic
- P2B9A Reductant Quality Sensor Circuit Intermittent/Erratic
- U02A2 Lost Communication With Reductant Quality Module
- U030C Software Incompatibility With Reductant Quality Module
Other components in Exhaust and Emissions
- Oxygen Sensor 326
- EGR Valve 150
- Catalytic Converter 142
- NOx Sensor 118
- Reductant Injector 107
- Exhaust Gas Temperature Sensor 95
- Reductant Tank 95
- Diesel Particulate Filter 76
- SCR Catalyst 65
- EGR Cooler 62
- Exhaust Gas Differential Pressure Sensor 58
- Fuel Tank Pressure Sensor 58
- Exhaust Pressure Control Valve 56
- Reductant Heater 55
- Reductant Pump 51
- EVAP Vent Valve 43
- Exhaust Aftertreatment Fuel Injector 42
- Charcoal Canister 33
- EGR Position Sensor 32
- Secondary Air Injection Pump 32
- Reductant Temperature Sensor 29
- EVAP Leak Detection Pump 29
- EVAP Purge Valve 27
- Particulate Matter Sensor 24
- Reductant Control Module 24
- Reductant Level Sensor 23
- Secondary Air Switching Valve 22
- EGR Temperature Sensor 21
- Secondary Air Check Valve 21
- Catalyst Heater 20
- Catalyst Temperature Sensor 20
- Fuel Filler Cap 18
- EGR Cooler Bypass Valve 16
- Exhaust Back Pressure Sensor 15
- Purge Flow Sensor 13
- Direct Ozone Reduction Catalyst 13
- EGR Vacuum Solenoid 9
- Fuel Vapour Temperature Sensor 5
- Fuel Additive Control Module 4
- Fuel Additive Tank 4
Information, not instruction
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