P2202 on Mercedes-Benz
NOx Sensor Circuit Low Voltage (Bank 1, Sensor 1)
P2202 on Mercedes-Benz vehicles indicates nox sensor circuit low voltage (bank 1, sensor 1). Au7o has documented this code across 1 Mercedes-Benz model — most commonly on V-Class. The PCM has detected that the signal voltage from the NOx (nitrogen oxide) sensor on Bank 1, Sensor 1 is lower than the expected operating range. The NOx sensor measures nitrogen-oxide content in the exhaust to manage the aftertreatment system (SCR/DEF on diesels or lean-burn emission control), so a low-voltage fault means the engine controller can no longer trust that reading. This is primarily a diesel and lean-burn emissions code and typically triggers reduced-emissions or limp-mode behavior. Typical repair costs on Mercedes-Benz range from $300 to $900, depending on the specific model and root cause.
Common Causes of P2202
- •Failed or contaminated NOx sensor element (Bank 1, Sensor 1)
- •Short to ground or low resistance in the NOx sensor signal or supply wiring
- •Corroded, loose, or damaged sensor connector / pins
- •Open or high-resistance ground or reference circuit causing low signal
- •Exhaust leak or soot/sulfur contamination affecting the sensor
- •Faulty NOx sensor control module or PCM/ECM (less common)
P2202 on Mercedes-Benz by Model
Mercedes-Benz V-Class(1 issue)
- AdBlue/SCR System Faults Triggering Limp Mode and No-Start Countdown2015-2020
On Euro 6 W447 diesels the SCR emissions system depends on NOx sensors (before and after the catalyst) and the AdBlue dosing system. A failed NOx sensor, dosing fault, or low/contaminated AdBlue escalates from a yellow warning to a red warning and finally a 'No start in X miles' countdown, after which the engine will not restart once switched off. The vehicle commonly drops into limp mode (restricted speed/power) before that. NOx sensor failure is one of the most frequently cited W447 emissions faults.
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View P2202 across all makes →Frequently Asked Questions
What does P2202 mean on Mercedes-Benz?▼
P2202 stands for "NOx Sensor Circuit Low Voltage (Bank 1, Sensor 1)." The PCM has detected that the signal voltage from the NOx (nitrogen oxide) sensor on Bank 1, Sensor 1 is lower than the expected operating range. The NOx sensor measures nitrogen-oxide content in the exhaust to manage the aftertreatment system (SCR/DEF on diesels or lean-burn emission control), so a low-voltage fault means the engine controller can no longer trust that reading. This is primarily a diesel and lean-burn emissions code and typically triggers reduced-emissions or limp-mode behavior. On Mercedes-Benz specifically, this code is documented across 1 model.
What causes P2202 on Mercedes-Benz vehicles?▼
Common causes on Mercedes-Benz: Failed or contaminated NOx sensor element (Bank 1, Sensor 1), Short to ground or low resistance in the NOx sensor signal or supply wiring, Corroded, loose, or damaged sensor connector / pins, Open or high-resistance ground or reference circuit causing low signal, Exhaust leak or soot/sulfur contamination affecting the sensor. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P2202 on a Mercedes-Benz?▼
Repair costs on Mercedes-Benz range from $300 to $900, depending on the specific model and root cause.
Which Mercedes-Benz models have P2202 documented?▼
Au7o has documented P2202 on 1 Mercedes-Benz model: V-Class.