P0405 on Opel: How to Diagnose & Fix
Exhaust Gas Recirculation Sensor 'A' Circuit Low
1 Opel model · 1 documented issue · 1 critical · $400-$1,200 repair
P0405 on Opel by model: symptoms, diagnosis and fix
The A17DTR/A17DTS 1.7 CDTI diesel in Astra J (2009-2015), Mokka A, and Meriva B suffers severe EGR valve carbon buildup, typically presenting between 80,000-150,000 km. Symptoms include power loss, limp mode, and rough idle. The EGR cooler can also crack, mixing coolant with intake flow.
Common Symptoms
- power loss
- limp mode
- rough idle
- EML warning
- black smoke
How to Fix
EGR valve clean or replacement (€400-€800 incl. labor). EGR delete is common but illegal in most markets and fails TÜV / MOT emissions tests. Walnut blasting helps the intake manifold simultaneously.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine Vauxhall/Opel 97376663 / 95523829 EGR valve
Astra J 1.7 CDTI A17DTR/A17DTS among the seller's listed engine codes; verify VIN/engine code and whether adaptation is required.
As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.
P0405 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 P0405 mean on a Opel?
P0405 stands for "Exhaust Gas Recirculation Sensor 'A' Circuit Low." P0405 is a generic OBD-II code meaning the engine computer detected an abnormally low voltage signal from the Exhaust Gas Recirculation (EGR) sensor 'A' circuit. This sensor reports the EGR valve's position or flow, which the computer uses to control exhaust gas recirculation for lowering emissions and combustion temperatures. A low signal indicates the reading is below the expected range, often due to a wiring or sensor fault. It mainly affects emissions and may cause light drivability issues but is not an immediate safety concern. On Opel it is documented across 1 model: Astra.
What are the most common causes of P0405?
The most common causes of P0405 are: Faulty EGR position sensor (or DPFE sensor), Open, shorted, or corroded EGR sensor wiring/connector, EGR valve stuck or carbon-clogged, Loss of reference voltage or ground to the sensor, Poor connector contact / pin corrosion, Damaged EGR valve assembly, PCM fault (rare). The specific cause varies by vehicle.
How much does it cost to fix P0405 on a Opel?
Published repair estimates on Opel range from $400 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.
Looking for P0405 on a different make?
View P0405 across all makes →Join 600+ people using Au7o to better understand their vehicles.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.