P246B on Volkswagen: How to Diagnose & Fix
Diesel Particulate Filter Active/Regeneration - Incorrect Conditions/Temperature Too Low - Bank 2
1 Volkswagen model · 1 documented issue · 1 critical · $300-$3,000 repair
P246B on Volkswagen by model: symptoms, diagnosis and fix
The diesel particulate filter (DPF) in TDI Passat models is prone to clogging, particularly in vehicles used primarily for short trips or city driving where the exhaust does not get hot enough for passive regeneration. A clogged DPF triggers regeneration cycles that increase fuel consumption and can eventually put the vehicle in limp mode if the filter becomes too saturated with soot.
Common Symptoms
- DPF warning light on dash
- Reduced power / limp mode
- Increased fuel consumption
- Frequent short regeneration cycles
- Strong exhaust smell during regen
How to Fix
Perform a forced DPF regeneration using VCDS or an OBD-II tool capable of commanding active regen. If the filter is heavily clogged, professional DPF cleaning services can restore it. In extreme cases, DPF replacement is necessary. Prevent future issues by taking the vehicle on highway drives of 20+ minutes regularly to allow passive regeneration. Use low-ash diesel oil (VW 507.00 spec).
Sources for this issue (1)
P246B 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 P246B mean on a Volkswagen?
P246B stands for "Diesel Particulate Filter Active/Regeneration - Incorrect Conditions/Temperature Too Low - Bank 2." This code indicates the engine computer detected that conditions were not correct to perform a proper regeneration (burn-off) cycle of the diesel particulate filter (DPF) on bank 2, typically because exhaust temperatures were too low. The DPF traps soot from diesel exhaust and must periodically heat up to roughly 600 C to burn that soot away. When the computer sees inconsistent temperature or sensor data over several drive cycles, it logs this code to warn that the filter cannot clean itself safely. Left unaddressed, the DPF can become clogged and restrict the exhaust. On Volkswagen it is documented across 1 model: Passat.
What are the most common causes of P246B?
The most common causes of P246B are: Short trips / low-speed driving preventing regeneration, Faulty exhaust gas temperature (EGT) sensor, Clogged or aged diesel particulate filter, Faulty DPF differential pressure sensor, Excess soot from a running engine fault (air leak, injector issue), Failed or aborted regeneration cycles, Wiring or connector faults on EGT sensors. The specific cause varies by vehicle.
How much does it cost to fix P246B on a Volkswagen?
Published repair estimates on Volkswagen range from $300 to $3,000 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 P246B on a different make?
View P246B across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.