EGR, DPF & AdBlue
Emissions system diagnostics, repair and software work. We keep your vehicle legal, efficient, and problem-free.
What EGR, DPF & AdBlue Are
EGR — Exhaust Gas Recirculation
Routes some exhaust gas back into the intake manifold to reduce combustion temperatures and NOx emissions. In controlled conditions it works well. But on short runs (stop-start use), older diesel vehicles, or vans doing frequent deliveries, the EGR causes issues: carbon build-up in the intake manifold, rough idle, poor fuel economy.
DPF — Diesel Particulate Filter
A physical filter in the exhaust that traps soot particles. It needs periodic regeneration — a high-temperature burn-off cycle to clear the accumulated soot. If your car doesn't do long enough runs to complete a full regeneration (motorway distances, steady-state cruising), the filter accumulates soot and eventually blocks.
When that happens, you get a warning light, power drops, fuel consumption increases, and eventually limp mode. The ECU is trying to force a regen but the filter is already saturated.
AdBlue (SCR Systems)
A urea solution injected into the exhaust to reduce NOx emissions. Selective Catalytic Reduction systems. Most modern commercial vehicles need it. Common issues: sensor failures (sometimes just loose connectors), dosing unit faults, or contamination in the system.
UK Law: What We Will & Won't Do
DPF removal is an MOT failure point — instant visual fail. It's illegal under UK environmental law. We won't do it, and we'll tell anyone requesting it why we won't.
What we CAN do: diagnose physical faults, force software regenerations when appropriate, repair software faults, reinstate systems correctly. If a filter is physically damaged or saturated beyond recovery, it needs professional replacement — we'll advise on that and can source the part.
When Software Regen Works vs When It Doesn't
Software Regen Works When:
The filter hasn't reached saturation, but the ECU simply hasn't commanded a regeneration cycle — common on vehicles with incomplete regen attempts or short-run use patterns. We can force a regen software command and the cycle completes successfully.
The filter has an electronic fault or sensor problem, not a physical blockage. We clear the fault and reinstate normal operation.
Physical Replacement Needed When:
The filter is physically saturated beyond recovery — it needs a complete burn-off temperature and duration that the standard regen cycle can't provide anymore. The filter media has degraded.
There's physical damage to the filter housing or internal structure.
What We Can Fix
DPF & Regeneration
- Diagnose DPF blockage vs sensor fault vs software fault
- Force DPF software regeneration (when appropriate and safe)
- Clear DPF fault codes and warning lights where the underlying cause is software-related
- Advise on physical DPF replacement if needed
EGR Systems
- Diagnose EGR valve faults: sticking, carbon build-up, electrical failures
- EGR cooler faults and blockage
- Software recalibration to manage EGR operation better on problem vehicles
- Clear EGR fault codes once the underlying issue is understood
AdBlue & SCR
- Diagnose NOx sensor failures and drift
- AdBlue level sensor faults (often just a sensor reset needed)
- Dosing unit electrical faults
- AdBlue system contamination and cleaning
FAQ
No — DPF removal for road use is illegal in the UK and is an instant MOT failure on visual inspection. We won't do it. If you're running a competition-only vehicle or off-road machine, that's a separate conversation — contact us separately. For road vehicles, removal isn't an option we'll offer.
Usually a faulty NOx sensor or AdBlue level sensor — the system doesn't always register a fresh fill correctly. Sometimes just a loose connector or a sensor that needs resetting. We diagnose the sensor chain, test the dosing unit, and fix what's actually wrong rather than just clearing the warning.
If the underlying cause was simply incomplete regen cycles (short runs, stop-start use), then yes — a forced software regen combined with a proper long run afterwards often resolves it permanently. But if there's a faulty sensor causing incorrect readings, or the filter is already physically saturated, the underlying fault needs fixing first. We diagnose which situation you're in.
It can be. An EGR fault left running causes carbon to build up in the intake manifold — an expensive job to clean properly. Much better to get it diagnosed now while it's just a sensor or valve issue, before it becomes a carbon cleaning job. Contact us to investigate what's triggering the fault.
Emissions System Issues?
Get professional diagnosis and repair for EGR, DPF, and AdBlue faults.