P11DC on Opel: How to Diagnose & Fix
NOx Sensor 2 Current Performance (Bank 1 Sensor 2)
1 Opel model · 1 documented issue · 1 critical · $250-$1,200 repair
P11DC on Opel by model: symptoms, diagnosis and fix
Diesel Grandland X models (1.5 BlueHDi/1.6 diesel with SCR after-treatment) frequently throw exhaust after-treatment faults. Owners see emissions warnings, reduced power/limp mode, and the countdown message 'Engine start prevented in XXX miles/km'. Common root causes are NOx sensor failure (range/performance faults), SCR system or AdBlue injector/pump faults, crystallised AdBlue, or poor-quality urea. If ignored, the car eventually refuses to start. Critical phase is commonly around 30,000-45,000 km.
Common Symptoms
- Emissions / exhaust after-treatment warning
- Reduced engine power / limp mode
- 'Starting impossible in XXX km/miles' message
- High AdBlue consumption
- Engine refuses to start
How to Fix
Diagnose with a scan tool to identify whether the fault is a NOx sensor, the SCR/AdBlue dosing system, or sensor wiring/connector corrosion. Typical fixes: replace the failed NOx sensor (upstream/downstream), clean or replace the AdBlue injector/pump, refill with quality AdBlue, and clear the codes/reset the countdown. Software updates from Stellantis exist for some after-treatment faults. Do not ignore the 'start prevented' countdown.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Halfords ISO 22241 AdBlue 10 L with pouring spout
Universal ISO 22241 AdBlue for SCR diesels. Add only to the dedicated AdBlue filler and follow the Grandland manual's quantity/recognition procedure; not a repair for a persistent SCR fault.
- Bosch 0281006851 upstream NOx sensor 9816276480
Opel/Vauxhall Grandland X 2018-on 1.5 BlueHDi/DV5 upstream sensor, OE 9816276480/Bosch 0281006851. VIN verification is offered; not downstream and not the older 1.6 diesel branch.
- Grandland 1.5 Turbo D AdBlue injector 3647595
Confirm VIN and old part number; not approved for the 1.6 diesel.
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Sources for this issue (2)
P11DC code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P11DC mean on a Opel?
P11DC stands for "NOx Sensor 2 Current Performance (Bank 1 Sensor 2)." P11DC indicates the engine control module has detected a current/performance fault with the downstream Nitrogen Oxide (NOx) sensor (Sensor 2, Bank 1), part of the Selective Catalytic Reduction (SCR) emissions system. The NOx sensor module reports an out-of-range or implausible signal to the ECM over the serial data line for more than the calibrated time, and the ECM stores the code. It signals the post-catalyst NOx reading is unreliable, which can disrupt emissions control and DEF/SCR dosing on diesels. On Opel it is documented across 1 model: Grandland.
What are the most common causes of P11DC?
The most common causes of P11DC are: Failed or aged downstream NOx sensor (Sensor 2 / Bank 1 Sensor 2), Damaged, corroded, or loose NOx sensor wiring, connector, or serial data line, Exhaust leak near the SCR catalyst or sensor location skewing readings, Contaminated or degraded SCR/DEF catalyst affecting NOx conversion, Engine performance/combustion issues (misfire, EGR fault) raising actual NOx, Faulty NOx sensor control module or ECM software fault. The specific cause varies by vehicle.
How much does it cost to fix P11DC on a Opel?
Published repair estimates on Opel range from $250 to $1,200 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.