NOx Inlet or Outlet Sensor Failure (200K+ Mile Normal Wear)
The VOLVO-MACK-NOX-SENSOR-FAILURE (Volvo/Mack D/MP Series) diesel fault code means: NOx Inlet or Outlet Sensor Failure (200K+ Mile Normal Wear). This is a serious severity code.
Unverified. We could not confirm this code's definition against freely available manufacturer documentation, so treat the meaning, severity and fix guidance on this page as unconfirmed. Check it against the manufacturer's service information for your exact model and serial range before acting on it. This page is kept out of search engines for that reason, and we are working through this family manual by manual.
- Keep driving?
- Short distances only
- DIY difficulty
- intermediate
- Estimated cost
- $400-$900
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View pilot availability →What Are the Symptoms of VOLVO-MACK-NOX-SENSOR-FAILURE?
- Amber Check Engine Light and SCR efficiency warning
- Progressive derate warning (55 mph then 5 mph)
- NOx reading frozen or stuck at a value
- Failed emissions test
- Increased or decreased DEF consumption
What Causes VOLVO-MACK-NOX-SENSOR-FAILURE? (Most Likely First)
- NOx sensor aged past typical service life (200-300K miles) Very Likely
- Contamination from DEF crystallization around sensor tip Likely
- Heat-damaged harness at sensor pigtail Possible
- SCR thermal event caused sensor damage Possible
- Connector corrosion Less Likely
Can I Still Drive with VOLVO-MACK-NOX-SENSOR-FAILURE?
Short distances only. VOLVO-MACK-NOX-SENSOR-FAILURE is rated serious severity. Keep trips short and get it diagnosed soon rather than waiting for symptoms to worsen.
Frequently Asked Questions
What does Volvo/Mack code NOX-SENSOR-FAILURE mean?
Volvo/Mack code NOX-SENSOR-FAILURE (NOx Inlet or Outlet Sensor Failure (200K+ Mile Normal Wear)) is a serious-severity diagnostic trouble code set on D11/MP7, D13/MP8, and D16/MP10 diesel engines in Volvo VNL/VNR and Mack Anthem/Pinnacle/Granite/Titan trucks. It indicates a fault in the NOx sensor system and should be read with Volvo Premium Tech Tool (PTT) or Mack Guided Diagnostics.
Can I drive a Volvo or Mack truck with code NOX-SENSOR-FAILURE?
Short distances may be acceptable to reach a repair facility, but the fault will escalate to derate (typically 55 mph then 5 mph on aftertreatment faults). Do not defer diagnosis beyond a shift.
How much does it cost to fix Volvo/Mack code NOX-SENSOR-FAILURE?
Typical repair falls in the range $400-$900. Sensor/wiring repairs are at the low end; EGR cooler, NOx sensor set, DEF pump, injector, or head work runs at the high end. Volvo PTT or Mack Guided Diagnostics is normally required for calibration and parameter programming.
Mechanics Guide Step-by-step diagnosis
How Do You Diagnose VOLVO-MACK-NOX-SENSOR-FAILURE?
Connect Volvo PTT or Mack Guided Diagnostics and read inlet/outlet NOx live values for plausibility; a frozen reading confirms sensor failure.
Inspect harness for heat damage or white urea crystallization at connector.
NOx sensors are $350-$500 each and come with integrated pigtail — sensor comes as an assembly.
Replace the offending sensor; if both are over 200K miles, replace both proactively.
After replacement, run the SCR self-test procedure via PTT or Guided Diagnostics and clear codes.
Verify the SCR conversion efficiency returns within spec after a warm-up cycle.
Which Vehicles Commonly Get VOLVO-MACK-NOX-SENSOR-FAILURE?
- Volvo VNL 760/860 with D13
- Volvo VNR 640 with D11/D13
- Mack Anthem with MP8
- Mack Pinnacle with MP7/MP8
- Mack Granite with MP7/MP8
- Mack Titan with MP10
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