P229F on Mercedes-Benz
NOx Sensor Circuit Range/Performance (Bank 1 Sensor 2)
P229F on Mercedes-Benz vehicles indicates nox sensor circuit range/performance (bank 1 sensor 2). Au7o has documented this code across 1 Mercedes-Benz model — most commonly on Sprinter. P229F indicates the engine control module detected a range/performance problem with the downstream NOx sensor on bank 1 (sensor 2), most common on diesel vehicles with SCR/AdBlue emissions systems. The NOx sensor measures nitrogen-oxide levels in the exhaust so the system can dose diesel exhaust fluid correctly and verify the catalyst is working. An implausible or out-of-range signal can trigger emissions warnings, reduced power, and on many diesels eventual no-start countdowns tied to emissions compliance. It is an emissions-system fault that should be addressed before it escalates. Typical repair costs on Mercedes-Benz range from $500 to $3,500, depending on the specific model and root cause.
Common Causes of P229F
- •Faulty downstream NOx sensor (bank 1 sensor 2)
- •Wiring or connector corrosion at the NOx sensor
- •Exhaust leak upstream of the sensor
- •Contaminated or incorrect diesel exhaust fluid (DEF/AdBlue)
- •SCR catalyst degradation
- •NOx sensor control-module communication fault
- •ECM software needing update/recalibration
P229F on Mercedes-Benz by Model
Mercedes-Benz Sprinter(1 issue)
- DEF/AdBlue SCR System Faults and Derate2014-2025
The Sprinter diesel exhaust fluid (DEF/AdBlue) selective catalytic reduction system is plagued by faults in the dosing module, NOx sensors, DEF heater, and SCR catalyst. Failures trigger the dreaded "engine derate" countdown that limits vehicle speed to 5 mph if not resolved, stranding commercial vehicles. The system is sensitive to DEF quality and cold weather.
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What does P229F mean on Mercedes-Benz?▼
P229F stands for "NOx Sensor Circuit Range/Performance (Bank 1 Sensor 2)." P229F indicates the engine control module detected a range/performance problem with the downstream NOx sensor on bank 1 (sensor 2), most common on diesel vehicles with SCR/AdBlue emissions systems. The NOx sensor measures nitrogen-oxide levels in the exhaust so the system can dose diesel exhaust fluid correctly and verify the catalyst is working. An implausible or out-of-range signal can trigger emissions warnings, reduced power, and on many diesels eventual no-start countdowns tied to emissions compliance. It is an emissions-system fault that should be addressed before it escalates. On Mercedes-Benz specifically, this code is documented across 1 model.
What causes P229F on Mercedes-Benz vehicles?▼
Common causes on Mercedes-Benz: Faulty downstream NOx sensor (bank 1 sensor 2), Wiring or connector corrosion at the NOx sensor, Exhaust leak upstream of the sensor, Contaminated or incorrect diesel exhaust fluid (DEF/AdBlue), SCR catalyst degradation. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P229F on a Mercedes-Benz?▼
Repair costs on Mercedes-Benz range from $500 to $3,500, depending on the specific model and root cause.
Which Mercedes-Benz models have P229F documented?▼
Au7o has documented P229F on 1 Mercedes-Benz model: Sprinter.