Frequently Asked Questions

A Diesel Particulate Filter (DPF) becomes blocked when soot builds up faster than the vehicle can burn it off through regeneration. This is commonly caused by frequent short journeys, stop-start driving, interrupted regeneration cycles, faulty sensors, boost leaks, EGR issues, or underlying engine faults. Commercial vehicles and diesel cars used mainly for urban driving are especially prone to DPF blockage.

In many cases, yes. A blocked DPF can often be professionally cleaned if the filter itself is still structurally sound and the underlying cause of the blockage is addressed. At Carbon Clean Co, we provide mobile DPF diagnostics and cleaning, assessing whether the filter can be recovered before costly replacement is considered.

This depends on the condition of the filter. If the DPF is blocked with soot but still intact, professional cleaning is often a far more cost-effective solution than replacement. However, if the filter is physically damaged, melted internally, or excessively contaminated with ash, replacement may be required. Proper diagnostics are essential before making that decision.

Repeated DPF blockages are usually a symptom of another underlying issue rather than the DPF itself. Common causes include faulty EGR valves, low Eolys fluid (on compatible vehicles), failed sensors, boost leaks, injector issues, excessive idling, or unsuitable driving patterns. Simply clearing the DPF without diagnosing the root cause often leads to repeat problems.

Driving with a partially blocked DPF may initially seem possible, but continued use can lead to reduced engine performance, limp mode, failed regenerations, excessive exhaust temperatures, turbocharger stress, and potentially expensive repairs. If warning lights are present, it is best to have the vehicle diagnosed as soon as possible.

DPF regeneration is the process where the vehicle burns accumulated soot from the diesel particulate filter at high temperatures. Some vehicles regenerate passively during longer motorway journeys, while others perform active regeneration by injecting extra fuel to raise exhaust temperatures. If regeneration repeatedly fails, the DPF can become blocked.

If regeneration fails repeatedly, soot levels continue to rise until the DPF becomes heavily restricted. This can trigger warning lights, reduced power, limp mode, poor fuel economy, and in severe cases may prevent further regeneration entirely. The underlying cause of the failed regeneration should always be investigated.

DPF cleaning costs vary depending on the vehicle, severity of the blockage, and whether further diagnostics are required. Carbon Clean Co offers transparent pricing for mobile DPF cleaning and diagnostics, with clear advice provided before any work is carried out. Prices begin at £190

Many modern diesel vehicles are programmed to prevent the engine from restarting if a serious AdBlue or SCR system fault is not resolved within a mileage countdown. This is part of the vehicle’s emissions compliance system. If ignored, the vehicle may eventually refuse to start until the underlying issue is diagnosed and repaired.

Yes. Many AdBlue-related faults can be professionally diagnosed and repaired without unnecessarily replacing expensive components. Common issues include faulty sensors, injector blockages, crystallisation, pump faults, electrical faults, and SCR communication errors. Proper diagnostics are essential to identify the true cause.

An AdBlue warning light can appear for several reasons, including low fluid level, faulty level sensors, SCR system faults, failed NOx sensors, crystallisation, blocked injectors, or communication faults within the emissions control system. A warning light does not always mean the fluid simply needs topping up.

SCR (Selective Catalytic Reduction) system faults can be caused by faulty NOx sensors, injector problems, AdBlue pump failure, crystallisation, electrical faults, fluid contamination, or communication issues between the engine ECU and emissions control components. Accurate diagnostics are essential to avoid unnecessary parts replacement.

Yes. AdBlue can form white crystal deposits if it leaks, dries out, or if injector dosing problems occur. Over time, crystallisation can block injectors, restrict fluid flow, damage components, and trigger SCR system warnings if left unresolved.

Yes. Carbon Clean Co provides professional diagnostics for AdBlue and SCR-related faults, helping identify the underlying cause of warning lights, no-restart countdowns, reduced performance, and emissions system errors.

Eolys fluid is a special diesel fuel additive used in certain vehicles fitted with a diesel particulate filter (DPF), primarily Peugeot, Citroën, Ford, Volvo, Mazda, and some Toyota diesel models. It helps lower the temperature needed to burn off soot during DPF regeneration, allowing the filter to clean itself more effectively.

Eolys fluid is commonly found in diesel vehicles from PSA-based manufacturers, including Peugeot and Citroën, as well as selected Ford, Volvo, Mazda, and Toyota diesel models that share similar emission system technology. If you are unsure whether your vehicle uses Eolys fluid, diagnostics can quickly confirm this.

The refill interval depends on the vehicle, driving style, and tank capacity, but many vehicles require Eolys fluid refilling somewhere between approximately 80,000 and 120,000 miles. Some vehicles will display a warning when levels become low, while others may only show faults once regeneration problems begin.

Low Eolys fluid can prevent the DPF from regenerating correctly, leading to rapid soot build-up, DPF warning lights, failed regenerations, reduced engine performance, limp mode, and potentially expensive DPF-related repairs if ignored.

Yes. On compatible vehicles, Carbon Clean Co performs the required diagnostic reset after refilling Eolys fluid so the vehicle recognises the refill correctly. Without resetting the system, warning messages or regeneration issues may remain even after the fluid has been topped up.

Carbon Clean Co is based in Leicestershire and provides mobile vehicle diagnostics and emission system services across a wide area of the East Midlands. We regularly cover Leicester, Nottingham, Derby, Loughborough, Melton Mowbary, Burton upon Trent, Hinckley, Coalville, and surrounding areas. If you are unsure whether we cover your location, feel free to get in touch.

Yes. Our fully mobile service is designed for convenience, allowing many diagnostics and emission-related services to be carried out at your home, provided there is suitable access and a safe working environment.

In many cases, yes. We regularly attend customer workplaces, business premises, and commercial depots where suitable access is available. This is particularly useful for busy customers and businesses wanting to minimise vehicle downtime.

Call-out charges may apply depending on your location, the type of service required, and the circumstances of the booking, particularly for longer-distance visits or emergency attendance. Any applicable charges will always be discussed clearly before the appointment is confirmed.

Yes. Carbon Clean Co accepts card payments for customer convenience, as well as other agreed payment methods where applicable. Payment details can be confirmed at the time of booking if needed.

A deposit may be required for certain bookings, particularly longer-distance appointments, specialist services, or bookings where parts, consumables, or significant travel time are involved. Any deposit requirements will always be explained clearly before your appointment is confirmed.

Yes. Carbon Clean Co can provide invoices for customers and businesses where required. This is particularly useful for commercial customers, fleet operators, and company vehicles.

Booking is simple. You can contact us by phone, website enquiry form, or other available contact methods to discuss your vehicle issue, location, and preferred appointment time. We will advise on the most suitable next steps based on the symptoms you are experiencing.