Nox Sensor Repair
NOx Sensor Fault Diagnosis & Replacement Across the West Midlands
A failed or misreading NOx sensor is one of the most common causes of AdBlue warning lights and countdown messages. We diagnose, replace, and calibrate NOx sensors on-site across the West Midlands.
What our NOx sensor service covers
Full diagnosis through to replacement and calibration — all carried out on-site.
- Full NOx sensor live data analysis and fault code reading
- Upstream and downstream sensor testing and comparison
- Sensor replacement with correct specification parts
- ECU calibration following replacement
- Post-replacement re-scan to confirm fault codes are clear
- Live data recheck to confirm sensor is reading correctly
How our NOx sensor repair works
Diagnosed properly. Replaced correctly. Calibrated to manufacturer specification.
Recent NOx sensor jobs
A sample of the NOx sensor repair work we carry out across the West Midlands.
Job summaries
Mercedes Sprinter — Coventry
Downstream NOx sensor failed. Sensor replaced and ECU calibration carried out. AdBlue warning cleared and has not returned.
BMW 5 Series — Birmingham
NOx sensor fault code alongside AdBlue countdown. Upstream sensor replaced on-site. Live data confirmed correct readings post-replacement.
Vauxhall Vivaro — Wolverhampton
Repeated NOx fault after a previous generic reset. Faulty sensor identified and replaced correctly with full calibration. Fault resolved.
Audi Q7 — Solihull
Both NOx sensors showing out-of-range readings. Both replaced and calibrated. Emissions test passed at subsequent MOT.
Reviews
Two garages had already cleared the code and charged me for it coming back. These guys actually fixed it properly first time.
Came to my driveway, diagnosed it, replaced the sensor and calibrated it all in under two hours. Brilliant.
Van passed its MOT after the NOx sensor was replaced. Really professional service from start to finish.
Explained exactly what had failed and why before doing anything. Didn't just replace parts and hope for the best.
What affects the cost
NOx sensor replacement costs vary depending on the vehicle and sensor specification required.
- Vehicle make, model, and sensor specification
- Whether one or both sensors require replacement
- ECU calibration complexity for your specific vehicle
- Whether a full diagnostic is required before replacement
- Your location within the West Midlands service area
Ready to book?
Call us or send your vehicle details and the warning showing on your dashboard.
Questions about NOx sensor repair
Quick answers before you book.
How do I know if my NOx sensor has failed?
The most common signs are an AdBlue warning light, a countdown message, a stored NOx sensor fault code in the ECU, or a failed MOT emissions test. The warning returning shortly after an AdBlue top-up is also a strong indicator that the NOx sensor rather than the fluid level is the problem.
Does the NOx sensor need calibrating after replacement?
Yes — and this is one of the most common reasons NOx sensor faults return after a replacement elsewhere. Fitting a new sensor without carrying out the correct ECU calibration means the vehicle's software doesn't recognise the new sensor correctly. We always calibrate as part of every sensor replacement.
Can you replace a NOx sensor on-site at my location?
Yes. We carry out NOx sensor replacements fully on-site at your home, workplace, or wherever the vehicle is located across the West Midlands. There's no need to take the vehicle to a garage or arrange recovery.
Will a NOx sensor replacement fix my AdBlue warning?
If the NOx sensor is confirmed as the root cause during our diagnostic scan, yes. However, we always carry out a full diagnostic before replacing any parts to make sure we're fixing the actual fault rather than guessing. AdBlue warnings can have several causes and it's important to identify the right one before spending money on parts.