NOX11 Sensor
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Mountain Pass
Joined: Feb 2016
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From: North Fork, Long Island N
NOX11 Sensor
While traveling towing the 5th wheel got a check engine light in my 2016 Lariat. Got the truck to a dealer, a scan showed NOX11 sensor failure. Sensor replaced, & we were on our way, 7hrs later. I was in no mood to chat at the time. What does the NOX11 sensor control?
John
John
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Joined: Nov 2001
Posts: 6,748
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From: Tallassee, ALabama
OXIDES OF NITROGREN (NOx) CONVERTING CATALYST MONITORING
Selective Catalyst Reduction Catalyst Efficiency Monitor
The SCR catalyst is monitored to ensure it is capable of NOx conversion. NOx concentrations upstream and
downstream of the SCR are measured with NOx sensors. Using these concentrations, the cumulative efficiency of
the SCR catalyst is calculated and compared to a threshold. If the cumulative efficiency is below this threshold at
the end of the sample period (approx 1 minute), a fault will be indicated.
The reductant, Diesel Exhaust Fluid (DEF), which is used as part of the SCR catalyst reaction, is monitored to
ensure the tank is not refilled with an improper reductant. After the SCR Catalyst Efficiency Monitor has completed
and the SCR has been determined to be functional, the efficiency monitor continues to calculate the cumulative
efficiency of the system, with a calibrated wait time between iterations of the monitor. Successive values for
cumulative efficiency are included in two filtering routines, one for short term efficiency and the other for long term
efficiency. The short term efficiency must be less than a threshold (0.35-0.55, depending on application) and the
difference between short and long term conversion efficiency must be greater than a threshold (0.10).
Selective Catalyst Reduction Catalyst Efficiency Monitor
The SCR catalyst is monitored to ensure it is capable of NOx conversion. NOx concentrations upstream and
downstream of the SCR are measured with NOx sensors. Using these concentrations, the cumulative efficiency of
the SCR catalyst is calculated and compared to a threshold. If the cumulative efficiency is below this threshold at
the end of the sample period (approx 1 minute), a fault will be indicated.
The reductant, Diesel Exhaust Fluid (DEF), which is used as part of the SCR catalyst reaction, is monitored to
ensure the tank is not refilled with an improper reductant. After the SCR Catalyst Efficiency Monitor has completed
and the SCR has been determined to be functional, the efficiency monitor continues to calculate the cumulative
efficiency of the system, with a calibrated wait time between iterations of the monitor. Successive values for
cumulative efficiency are included in two filtering routines, one for short term efficiency and the other for long term
efficiency. The short term efficiency must be less than a threshold (0.35-0.55, depending on application) and the
difference between short and long term conversion efficiency must be greater than a threshold (0.10).
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Rubicante
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
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Apr 20, 2000 08:52 PM
