NOx sensor failure
Attaches to nox-sensor at component level · Emissions · carried by 22 variants across 8 chassis
Overview
NOx sensor failure is a common fault recorded against nox-sensor at component level, typically from 90–180k km. It shows up as engine warning light, noticeably worse fuel consumption, loss of lean-burn mode. Where it's documented, the repair runs €300–€600 (sensor fitted and coded, costs dated 2026-07), and it can be checked before you buy. 22 variants across 8 chassis in this database inherit it.
What happens
Symptom. Engine warning light, noticeably worse fuel consumption, loss of lean-burn mode.
Cause. The NOx sensor in the exhaust degrades. The engine then runs permanently rich, which is drivable but expensive.
How to check it
OBD scan
Scan for NOx sensor and lean-mode codes. Ask the seller what the car returns on a run. A lean-burn four that drinks like a six has a dead sensor.
Mandatory. A seller who refuses a scan has answered the question.
Every variant that carries this
| Variant | Chassis | Body | Years | Risk | Good buy | Cost as % of good buy |
|---|---|---|---|---|---|---|
| 320i N43 | E90 | sedan | 2007–2011 | R4 | €3,950 | 11% |
| 320i N43 | E91 | wagon | 2007–2011 | R4 | €4,200 | 11% |
| 320i N43 | E92 | coupe | 2007–2011 | R4 | €4,550 | 10% |
| 320i N43 | E93 | convertible | 2007–2011 | R4 | €4,450 | 10% |
| 325i N53 | E90 | sedan | 2007–2011 | R4 | €5,250 | 9% |
| 325i N53 | E91 | wagon | 2007–2012 | R4 | €5,550 | 8% |
| 325i N53 | E92 | coupe | 2007–2013 | R4 | €6,050 | 7% |
| 325i N53 | E93 | convertible | 2007–2013 | R4 | €5,900 | 8% |
| 330i N53 | E90 | sedan | 2007–2011 | R4 | €6,000 | 8% |
| 330i N53 | E91 | wagon | 2007–2011 | R4 | €6,350 | 7% |
| 330i N53 | E92 | coupe | 2007–2011 | R4 | €6,900 | 7% |
| 330i N53 | E93 | convertible | 2007–2011 | R4 | €6,750 | 7% |
| 116i N43B16 | E87 | hatchback | 2007–2011 | R3 | €3,500 | 13% |
| 116i N43B16 | E81 | hatchback | 2007–2011 | R3 | €3,100 | 15% |
| 118i N43 | E87 | hatchback | 2007–2011 | R3 | €3,900 | 12% |
| 118i N43 | E81 | hatchback | 2007–2011 | R3 | €3,450 | 13% |
| 118i N43 | E82 | coupe | 2007–2011 | R3 | €4,000 | 11% |
| 118i N43 | E88 | convertible | 2008–2011 | R3 | €4,200 | 11% |
| 120i N43 | E87 | hatchback | 2007–2011 | R3 | €4,250 | 11% |
| 120i N43 | E81 | hatchback | 2007–2011 | R3 | €3,800 | 12% |
| 120i N43 | E82 | coupe | 2007–2011 | R3 | €4,400 | 10% |
| 120i N43 | E88 | convertible | 2008–2011 | R3 | €4,650 | 10% |
The last column is the point. The same repair is an inconvenience on one variant and a reason to scrap the car on another. A failure costing a quarter of the vehicle's value changes the purchase decision regardless of how rare it is.