Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Intake NOX Sensor
The intake NOx sensor is the first sensor mounted on the aftertreatment tubing, just in front of the DOC. This sensor measures the quantity of NOx in the exhaust gas before it enters the aftertreatment system. The intake NOx sensor includes a unique processor that is mounted externally from the sensor, and also includes a heater to bring the sensor to operating temperature quickly. The intake NOx sensor also detects the oxygen level in the exhaust.
The ECM compares the intake and outlet NOx sensor readings to determine the amount of NOx reduction that is achieved in the aftertreatment system, and to determine how much DEF to inject into the exhaust stream.
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.