DPF Initial Assessment

DPF Diagnostic Report

Keeping You Informed

The technician carrying out the DPF Initial Assessment on your vehicle will maintain a log of the results from the investigations.

This, along with the DTC error log printout from the code scan will formulate a concise report for your consideration. At the bottom of the report the technician will formulate a conclusion for you along with the recommendations for repairs.

Your customer service advisor will prepare estimates from this report and provide you with copies of the report along with the quotations for repair. This can be done by email or telephone if you have elected not to wait with your car during the initial assessment.

If you decide against repairs at this stage we will raise an invoice for the Initial Assessment and you will sign a cessation of works at the time of vehicle release.

If you accept our repair estimates new job sheets will be raised for those works and the Initial Assessment fee will be waivered as a gesture of goodwill.


From £55

Free with Repairs


From £195

Disclaimer Required


From £250

Disclaimer Required


From £750

Aftermarket Installed

Other Repairs

When diagnosing a DPF problem we may identify other faults with the system that have caused the blockage, such as a sensor or upstream failure such as EGR Valve faults. When we prepare the report and estimates for the most appropriate solution, we will include estimates for any other repairs required. Failure to do these may result in the DPF blocking up again in a short period of time or excessive emissions in the case of removal. Please heed our advice, we aren't out to rip you off, we just know what we're talking about and what will cause further problems.

Request Information Pack

Common Other Repairs

Oil Flush & Filter

For best practice we would always recommend having an oil flush and filter renewal with DPF Repairs.

A DPF becoming blocked causes the system to continously attempt regeneration (up until the filter reaches maximum capacity for regen) which involves injecting additional diesel through the system.

This tends to contaminate the oil, hence the recommendation to flush the oil and renew the filter.

From £65 (Avg 4cyl car)

Intake System Decoking

An unfortunate side effect of DPF problems tends to be intake system carbon buildup.

Basically the soot and carbon deposits from the diesel system coke up the intake pipes, manifolds, egr valves etc etc. The volume of soot and carbon is much increased once the DPF becomes blocked and inefficient.

We offer multiple intake system decarb options, you'll receive more information from your customer service advisor.

From £95 (Most Cars)

Intake System Leaks

One of the main causes we find for DPF and carbon problems is an undetected intake system leak.

A small split in a pipe may not cause sufficient deviation from expected values for a MAF fault code to trigger, however it will be having an effect on the carbon build up and subsequent DPF status.

We offer a Smoke Pro Plus leak detector test which will highlight any intake system leaks.

From £25 (Basic Check)

EGR Valve Actuators

Exhaust Gas Recirculation basically recirculates a portion of exhaust gases back into the engine cylinders.

The valve is controlled by either a vacuum based or an electronic actuator valve which opens or closes to admit the exhaust under certain conditions. EGR Valve actuators stuck open or closed cause DPF issues.

EGR Valve cleaning can help, alternatively a new part may be required.

From £125 (Ultrasonic Cleaning)

EGR Valve Blanking

EGR Valves can be unreliable and cause problems and as they are a quite expensive part it has become popular under certain circumstances to blank the valve and bypass it from the system.

Mechanical blanking off is required and an engine ECU map adjustment to maintain emission standards.

There are pros & cons to all modifications, request an info pack or ask about this.

From £295 (Full Process)

Swirl Flap Blanking

Swirl Flaps are small butterly valves fitted to the intake manifold just before the cylinder head intake ports and operated with either a vacuum based or electronic servo mechanism.

Carbon build up on the flaps cause them to stick in one position and strain the system. Flaps can break & get sucked though the engine causing catastrophic failure.

Swirl Flap Bypass is therefore very popular as a precaution.

From £165 (Full Process)

Mass Air Flow Faults

The MAF sensor is used to measure the mass flow rate of air entering the engine.

The purpose of this is for the engine control unit to calculate the correct fuel mass. This means that if the mass air flow sensor or associated pipes have a fault, the engine will over or under fuel. This tends to increase carbon build up.

MAF faults need resolving.

From £55 (Diagnosis)

Sensor Faults

The multitude of sensors on the intake and exhaust system are all linked to the whole system running correctly.

Any sensor faults can trigger error codes & poor running. Even minor inefficiencies or variations can cause carbon build up or inoperation of the DPF regeneration process. A sure way to get a blocked DPF.

Sensor faults need identifying.

From £55 (Diagnosis)

Injector Problems

The injectors obviously inject the fuel entering the engine.

If an injector develops a fault the engine will be over or under fuelling. Not only is this bad for the cylinders but it will also lead to increased carbonisation and soot build up. Injector bench testing tends to be the best way of confirming injector status.

Injector cleaning is popular.

From £15 (Per Injecter Test)

Turbo Actuator Issues

The turbo actuator (also known as wastegate actuator) is responsible for controlling the boost output from the turbo by providing a pressure release valve diverting the gases away from the turbine wheel.

Pressure & heat are a recipe for wear & tear. The actuator spring will weaken & allow premature opening or the diagphram could fail.

An EML will likely illuminate, always get this checked!

From £55 (Diagnosis)

Turbo Problems

The turbocharger works hard and if a problem does develop it would be wise not to ignore it!

Turbochargers get carbonised just like the rest of the system and a Turbo ChemClean will do wonders as a preventative maintenance routine. Keeping the turbine clean definitely increases longevity.

We offer Turbo ChemCleaning or in worse case scenarios replacement of the turbocharger.

From £65 (Turbo ChemClean)

Carbon Treatments

All engines produce carbon as a side effect of the engine combustion process. Carbon Buildup Causes All Sorts of Problems!

Unfortunately not all of the carbon gets emitted via the exhaust system (to be filtered by the DPF), with modern recircularisation systems carbon deposits build up in the intake system. Decarbonisation prevents bigger issues.

We offer Additive Treatments, Chemical Cleaning & Walnut Blasting.

From £95 (ChemCleaning)

Common DTCs

DPF & Related System Error Codes

Error Code Description Causes & Symptoms
P0068 MAP/MAF Throttle Position Correlation Air Flow Deviation from Expected Values
P1400 DPFE Circuit Low Input DPF sensor has triggered fault
P1406 Exhaust Gas Recirculation (EGR) Position Sensor Performance EGR Valve fault is present