DPF & Diesel
DPF Diagnostics
A DPF warning is the end of a chain of events, not the start. Finding out why the filter is loading up is the part that saves money.
DPF light on?
What we check
- Soot and ash load values reported by the engine management
- Differential pressure sensor readings and sensor condition
- Exhaust gas temperature sensors
- EGR valve and cooler operation
- Boost pressure, leaks and turbo condition
- Injector correction values and combustion quality
- Regeneration history and why regenerations are being interrupted
- How and where the vehicle is driven
Why we do not promise a quick fix
Regeneration only works if the filter and the engine are in a condition to regenerate. If a sensor is reading incorrectly, the EGR is stuck, boost is low or injectors are worn, the filter will simply load up again. We will tell you what the data shows and what the realistic options are, which sometimes includes replacement.
Possible outcomes after diagnosis
- A forced or assisted regeneration where the filter is suitable
- Repair of the underlying fault — sensor, EGR, boost leak, injector or cooling
- Filter cleaning or replacement where the ash load is too high
- Advice on driving patterns where short journeys are the main cause
What we will not do
We do not remove DPFs. Removing or defeating emissions equipment on a road vehicle is not something we offer.
Frequently asked questions
DPF warning light?
Our work
Recent jobs from our workshop
Photographs taken during work carried out at our Iver workshop.
Soot-blocked EGR port removed for cleaning
Soot in the inlet ports after high-mileage diesel use
Damaged turbo compressor wheel found on inspection
Ford & Transit
Related Ford and Transit work
Wet belts, diesel diagnostics and DPF work on Ford cars and Transit vans — each page covers a different part of the job.
Ford Repairs & ServicingFord cars and vans make up a good share of the work that comes through our Iver workshop. This page covers how we approach Ford repairs generally — the belt-in-oil pages go into the timing and oil pump drive work in detail.Read more Ford Transit Custom RepairsThe Transit Custom is a working van, and the faults we see reflect that — high mileage, heavy loads and a lot of short urban journeys. Here is what tends to come in, and how we approach it.Read more Ford Wet Belt ReplacementFord's belt-in-oil designs are among the most common wet belt systems on UK roads, and among the most talked about. We replace them properly, including the oil pump drive.Read more Ford EcoBlue Wet Belt ReplacementEcoBlue diesels use a belt-in-oil timing drive. Owners often first hear about it when an oil pressure warning appears — which is the worst time to find out.Read more Ford Transit Custom Wet Belt ReplacementThe Transit Custom is one of the hardest-working vans in the country, and its belt-in-oil timing drive is one of the jobs owners cannot afford to leave.Read more Diesel DiagnosticsModern diesels combine high-pressure fuelling, turbocharging, exhaust gas recirculation and after-treatment. When one part of that system drifts, the symptoms usually show up somewhere else.Read more Timing Belt Replacement in IverThe timing belt keeps the crankshaft and camshafts turning in step. If it fails in service, the damage is usually to the engine rather than the belt.Read more
Advice
Helpful reading on this fault
DPF light on? What it means and what not to doA DPF light is a warning, not a failure. What you do in the next few hundred miles decides whether this is cheap or expensive.Read more DPF cleaning or replacement — which do you need?Cleaning a filter that blocked for a mechanical reason just buys time. Start with why it blocked.Read more Signs your DPF is blocking upA DPF rarely blocks without warning. These are the signs worth acting on before it becomes a replacement.Read more
Symptoms
Symptoms that often lead to this repair
Look up what your car is doing and read what it commonly means.
Car stuck in limp modeLimp mode is a protection strategy, not a fault in itself. The control unit has seen a reading it does not trust and has reduced power to keep things safe.Read more DPF warning light onThe DPF light means soot has built up beyond the level the system is happy with. Whether a drive will clear it depends on why it built up.Read more Black smoke from a diesel exhaustBlack smoke is unburnt fuel. On a modern diesel with a DPF it usually also means extra soot heading into the filter.Read more Car losing power when acceleratingLoss of power is either a fuelling, air or protection issue. Live data under load is what separates them rather than guesswork.Read more Turbo failure symptomsTurbos rarely fail without a reason. Oil supply, oil condition and blocked exhaust flow are common contributors, and replacing the turbo alone can repeat the failure.Read more EGR valve symptomsEGR valves soot up over time, particularly on cars used for short journeys. The symptoms overlap with several other faults, so testing matters.Read more Rattling noise from under the carRattles are located by loading and tapping components with the car on a lift, because a loose shield can sound exactly like something far more serious.Read more Car jerking when acceleratingJerking under load usually means the engine is briefly not getting the fuel, air or spark it needs — live data while driving is the quickest route to the cause.Read more Exhaust blowing noiseA blowing exhaust changes the sound of the car and can affect emissions readings and sensor behaviour as well as noise.Read more
Related
You may also need
DPF RegenerationRegeneration burns accumulated soot out of the filter. It is effective when the filter and the engine are in a fit state — and pointless when they are not.Read more Diesel DiagnosticsModern diesels combine high-pressure fuelling, turbocharging, exhaust gas recirculation and after-treatment. When one part of that system drifts, the symptoms usually show up somewhere else.Read more EGR Valve Repair & ReplacementThe EGR system recirculates a measured amount of exhaust gas back into the engine. When it sticks, everything downstream suffers — including the DPF.Read more Turbo ReplacementTurbo failure often has an underlying cause. Oil supply, restriction and boost control are checked first — otherwise the new turbo goes the same way as the old one.Read more Injector Diagnostics & Injector-Related RepairsInjector faults imitate a lot of other problems. Testing the injector data before replacing anything avoids fitting expensive parts the engine did not need.Read more
Talk to us about dpf diagnostics
Based in Iver, covering West London, Berkshire and South Buckinghamshire. Send your registration and we will quote for your vehicle.