Wallace Performance | Diagnostic Services

Our range of diagnostic services include:

	Engine Management faults
	ABS Faults
	Airbag Faults
	Misfire and poor running/idling faults
	Wiring faults

Modern day vehicles are now fitted with electronic management which control just about everything your car does. How it drives, accelerates, starts first turn of the key, delivers fuel etc. This makes modern day cars much more economical and responsive. This is done by using a multitude of sensors located throughout the engine. When all these sensors are working, the car will be at its best.

HOWEVER

If one of these sensors decides to fail then the car will more than likely experience a problem. Now you may think, how do we know if there are any sensors that have developed a fault? This is where you and the car come in;

When you switch on the ignition of your car you will find lots of lights shine out at you, some red, some amber and some maybe green. Once the car has started these lights should go out after about 5 seconds maximum. They should continue to be extinguished whilst normal driving. You may now ask then, well, what are these lights for? Well, as you approach a set of traffic lights you will find three lights, Green, Amber and Red. They mean, Clear to go, Proceed with caution and STOP! The same applies if you see any of these lights appear on your dashboard:

	Green – Clear to go or generally everything is fine ie your indicators flash green when activated
	Amber – Proceed with caution; This meaning, something is not quite right but you may continue with caution. Lights on your dashboard are sometimes indicated by amber ABS, ESP, SERVICE, OIL and various other symbols that you may not know the meaning of as yet (referring to the vehicle handbook will tell you the meaning of these).
	Red – STOP!!! And I mean STOP!!! Any further proceedings WILL cause damage or something has failed and requires you to go no further. Lights that are generally associated with red are, Oil lights and Battery lights.

Right, ok, you’ve learned about the colours but what do you do after you have seen these. Green is perfectly fine but amber you need to get this problem identified before anything else can happen. Remember the traffic light sequence? Green > Amber> RED. As soon as you see amber you should take your car to a specialist such as Wallace Performance to get this problem rectified. If you see a red light appear you need to call us Urgently so that we may arrange the uplift of your car from it’s current place. Do not travel any further when you see a RED light.

Once that is understood you need to understand what we do to diagnose and rectify these faults. If all you require is your car fixed just stop here and call 01224 708444 but if you want to know a bit more and are interested in what we do and how we can help read on...

Modern engines use various different what we call “Control Units,” in order to make the running and safety of the car significantly better than of older cars. They each have a separate purpose to serve and these fall into different categories;

	Engine Management
	Anti-lock/skid Braking System (ABS)
	Airbag safe system or SRS sometime (Supplementary Restraint System)

Now these are the three main categories and are present in almost all modern day cars that make your car nice to drive, stop safely and well, crash more safely but what if there is a fault with one of these systems? How do you know when they are not functioning as they should? Well (generally), this is the easier bit for you to spot.

When you turn your ignition on in your car you will see all the lights that light up on your dashboard. These will say various things but the first three we will look at is the above. The Engine Management advisory light is amber in colour and can be indicated by a number of different symbols hence this is where you have to look up your manual and pick out the correct symbol but generally it looks like a ragged box shape. The Anti-lock/skid Braking System or ABS light is very easy and always amber and says ABS or can sometimes say ESC or ESP. The latter is to do with traction control but generally it is shown as an ABS light. Last for now is the Airbag light, it is sometimes amber in colour but generally red. Now I know I said that you must not travel any further if you see a red light on your dash, well, the truth is, you can continue to drive with an airbag red light safely but you cannot crash as safely as you could if you had airbags. See what I’m getting at? The red lights can lead to very serious things happening to you or your car.

Right then, let’s get onto some interesting and good news now. When you see one of these lights appear, there is a fault with your car. What’s good news about that you might say? Well, this is more down to the fact that with modern day cars it saves you lots of man hours diagnosing a fault with a faithful test light and multimeter as now it can be plugged into a diagnostic computer and up comes on the screen what the fault is (or gives the person a head start to find the problem). Once this fault is shown, the part can either be replaced or the part fixed in some way. Generally hassle free! Now you may say to yourself, that’s great, all I need to do now is buy one of these gadgets and I can fix my own car! Now if it was that simple, people like us would not be in a job. The trouble is if you can’t interpret what the computer is saying then you will struggle to find the fault. I’ll give you an example;

Most cars measure the amount of air that passes into their engines by using what is called a “Mass Air Flow” Meter (MAF). This is a hollow tube with a sensor inside it that measures the air passing over it. I don’t want to go into too much detail here but basically the more air that passes through it, the higher the voltage is given. Now if a sensor breaks or is damaged it can send the computer a “High Voltage” warning and indicate it’s happening through the Mass Air Flow meter. You say to yourself “Bingo!” and go and splash out on a new MAF costing average about £300 replace it, start the engine, give it a rev and …. Eh? The light is still on?? Why’s this? You then decide to take the vehicle to our centre, you tell one of guys what you’ve done, we then open your bonnet and proceed to show you the split in the pipe that leads to the inlet manifold of your engine. We replace this and suddenly the light goes off. I’m afraid due to a MAF being an electronic part you will not get your money back for this.

The second reason for not buying one of these computers is that they are expensive. The one we use is approx £8000 just for the machine alone.

If you ever see what is done when we plug in the computer you will think it is very easily done and why do we have to charge for doing this. Well, the honest answer is, we have to pay for the machine, the premises, the advertising, the man that does the work, the person that prints the invoice, the printer that prints your paper… It adds up.

So what do we charge for a basic diagnostic, plug in and see roughly what is wrong? £30 including VAT is what we charge. This covers the result of the machine ie it will either tell us exactly what is wrong OR for the bigger faults where about the fault lies in. We charge this because a lot of people want to take their car away and fix it themselves. We have no problem with this. If you are however not mechanically minded and would like us to fix it, we will then book you in to get the work carried out, fault fixed and completed.

I will add more to this page when I’ve got time so please look out for various new sections where I will discuss the various control units and give you an insight into the workings of these.

Gavin Wallace
Wallace Performance

Wallace Performance, Units 17+18, Murcar Commercial Pk, BOD, Aberdeen, AB23 8JW