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Audi Common Faults​

Check engine light on? Engine running rough?  Here you will find some answers to the most frequently diagnosed Audi problems brought into TWG.  We do not recommend you assume that the answer here directly relates to your car.  Accurate diagnosis of a problem typically saves you money. And, you should know that often third parties will misdiagnose a car for what appears to be similar problems or related diagnostic codes. Also ever heard the saying “a little knowledge is dangerous” its true! to much Googling can cost you extra money if you assume your problems are related.​

Engine has poor performance at high rev range

The air mass meter could be at fault, an air mass meter is also referred to as a mass air flow sensor (MAF). An air mass is essentially a device meant to measure the flow of air into the engine. This sensor is required for the engine control unit (ECU) to balance as well as deliver the accurate fuel to the engine. Inside the sensor is a wire coil that’s heated up to a constant temperature once air is passed by the wire it changes the resistance od the current supplied to the engine control unit. Overtime the wire coil gets contaminated giving the wrong reading resulting in poor performance and rough idle.

An old trick of the trade is to unplug the MAF and see if the performance improves because this will direct the engine into limp home giving a default fuel supply. The vehicle must be connected to a Mercedes Star Diagnosis to confirm any issues.

Engine Misfire at idle and Acceleration

Failure of the Ignition coil on a Audi is by far the single most common mechanical problem. It is also among the prime reason behind engine misfire. The solution is instalment of good quality OE spark plugs and coil packs and tuning of the engine to factory specs. Thankfully ignition coils or spark plugs are not expensive and will cost anywhere between £100 to £200 for parts as well as labour charges. The coil costs around £30 each.

TT Instrument Cluster fail

The Audi TT (MK1 1999-2006) dashboard known as the instrument cluster has an LCD centre display panel which is very common to fail. The screen display can become unreadable, pixelated or even be blank. Also, the fuel gauge can fail giving incorrect readings or even sometimes no reading at all. The fix is to remove the unit and send for repair.

Timing Belt Failure

Engine stops and will not start, when trying to start engine turns over very quickly.

The Timing Bent is a method of turning the Camshaft by the Crankshaft and should be synchronized, once the belt becomes loose or breaks the valve train comes in contact with the Pistons Engine damage is almost inevitable.

Timing Belt Replacement: One of the most important services that should be performed on your vehicle is a timing belt inspection or replacement. If the timing belt is neglected and allowed to break, thousands of pounds of damage could occur to your engine. The recommended intervals for timing belt replacement vary between 40k and 80k miles depending upon the year and model of the vehicle. When changing the Timing belt it is good practise to change the idler pulleys and the water pump at the same time.

Audi Turbo Over-Under boosting limp home mode

Loss of power, over boosting, under boosting, or no power, the VNT turbo vanes stick causing, low boost, limp mode, low power, limp home mode, Turbocharger actuator rod seized, is a sure diagnosis for clogged up vanes..Turbochargers with carbon build-up inside the turbo stick onto the variable vanes which causes the vanes to become stiff to move..Turbo cleaners are available from three of the best value & quality turbo cleaner brands on the market Forte turbo cleaner and Wynn’s turbo cleaner also we like Tunap, these can be used for a quick turbocharger repair or clean out of sticky vanes, when the turbocharger vanes are sticking or turbo vanes stuck for both petrol Turbos and diesel Turbos.

Also an added bonus these turbo cleaners will also clean the EGR valve on the engines.

Audi Blocked DPF


The electronic indicator lights, the vehicle has no more power and extremely high fuel consumption? The diesel particulate filter has only a limited capacity to store particulates. From a certain amount of soot, the soot particles must be burned in a regeneration process to CO2 and ashes. Different reasons can mean the regeneration process does not start and in consequence the DPF gets clogged with soot particles.

Possible causes:

  • Defective or not fully functioning injectors
  • Sooty or coked EGR valve
  • Different qualities of fuel or Bio fuels
  • Short distance driving profile


Particulate filters can be cleaned in an installed condition, rapidly, simply and significantly more economically than replacing them.

  • Used when regeneration is no longer possible
  • Cleaning to almost new condition possible
  • No expensive new installation
  • Cleaning without disassembly of the particulate filter
  • Non-flammable
  • Neutral ash and metal-free formulation
  • Evaporates completely

Compatible with other materials

An overloaded DPF: That is expensive.

For replacement of the part customers have to pay a lot of money. For a new diesel particulate filter between £600 and £4000 would be charged. In addition a prolonged stay in the workshop and a rental car has to be organised. TWG Solution: Cleaning instead of replacement.