Don't get too hung up on the terms used, the engine control unit needs to know if the engine is running and how fast it is running. Some engines have a sensor that measures this from the bottom end, at the crankshaft or flywheel, hence the term crank sensor. A Hall sensor can be used for numerous applications one of which is for measuring engine speed, it's called a Hall sensor because of the way that it works, it makes use of a natural phenomena called the Hall effect named after Edwin Hall who discovered it. Your Polo has a Hall sensor built into the distributor that measures the engine speed. On the side of the distributor there is a 3 pin electrical connection, if you unplug this and connect a voltmeter between the two outer pins and switch the ignition on you should get a reading of at least 9 Volts. The next step is to check the continuity of the three wires from the plug to the engine control unit. This is where you need a wiring diagram from your workshop manual and you will need to find and unplug the engine control unit. You will need to work out which pin numbers on the engine control unit correspond to each of the 3 wires at the distributor plug. The maximum resistance should be 1.5 ohms, anything higher and you have a wiring fault. The final check is for a short circuit (low resistance) between each of the 3 wires at the distributor plug (engine control unit still unplugged), the resistance should be so high that it is infinite. Once you have the results, you need to work out what they are telling you. If there is no fault in the wiring and you have at least 9 Volts at the two outer pins, the Hall sensor is faulty, as it is built into the distributor, the distributor will need to be replaced. If there is no fault in the wiring and no voltage at the two outer pins, the engine control unit will need replacing. Just to add, the above is a procedure that I followed from a workshop manual when fixing a Skoda Octavia with the same fault and the same engine. If you have any doubts about it, call in a professional (mobile mechanic) to fix the car. All in it shouldn't cost more than £200 if the distributor is at fault, it will be much more if it's the engine control unit.

By diagnosis, I assume that you had someone plug in a code reader to check for any stored fault codes, what was the code and text for it? Would this be engine code AEE, you would find this on the data sticker in the boot and service book or on a sticker on the cam belt cover. The engine speed sensor for this is in the distributor, replacing it means replacing the distributor, they were around £80 from VW and are an exchange unit. If you can get a workshop manual, there are some tests that you can carry out with a multi meter to confirm that it is faulty. A failed engine speed sensor will cause the engine to stop and not restart.

They have a usage policy, it's on page 22 of this document: http://www.theaa.com/breakdown-cover/pdfs/breakdown-cover-policy-feb-2011.pdf

I'm not a fan of pattern catalytic convertors, we went through the same with one for a VW group car. It just kept popping the light on and logging an efficiency fault. We ended up sending it back and fitting a genuine one, the customer did have to pay the extra for the genuine part. Unfortunately this may not be an option for a Saab, given the current poor parts supply situation, 2,000 back ordered lines from what I hear. It seems odd that the efficiency is tested from a cold start as catalytic convertors need to be hot to work and the feedback system is in open loop when cold. Did the garage try erasing the learned values from the ECU?, so that it can re-learn its fuel trims.

Given the time between the MOT and the inspection by the Ford garage, it is entirely feasible that a small leak has got much worse. On a roller brake test, you get the roller to move each wheel in turn whilst you apply either the service (foot) brake or parking (hand) brake and read off for each wheel each brakes recorded effort. Each brake adds to the overall efficiecy reading, which for the service brake is 50% and the parking brake 16% (for this car), calculated against a brake testing weight given by the MOT computer. These %ages are quite low, but that's the MOT standard. So if the test weight is 1000Kg, the fronts record 200IKg each, you only need 50Kg on each rear to pass. Rear brakes might not record any more than 100Kg, if they are not drastically low and the overall efficiency on all four wheels is there, the efficiency requirement is met. There is an additional check where both wheels are driven by the rollers simultaneously and the brake is applied to check that they are increasing/decreasing at roughly the same rate. There is no requirement to check brake balance on non steered axles. For assessing corrosion a corrosion assessment tool (CAT) is used. It's basically a 6" hammer, the head is made out of plastic with one end flat and the other end domed, the handle is metal which has a blade at one end for scraping off loose rust/underseal. Any suspect area is lightly tapped with the plastic end and the sound produced is listened to, if corrosion is suspected finger and thumb presure is used, sometimes your fingers will go through or you'll hear/feel the panel cracking or flexing. Even if you hammer through with the CAT, the panel is severely weakened, as there is no way that the CAT will go through sound metal. Boiling water or even removing the shoes and boiling them in a pan is good for removing brake fluid contamination. The MOT is not about predicting what's going to fail in the future, if it moves to bi annual testing people are going to assume that everything for the next two years will be OK. With regard to failing a split boot, you can't, every fail is picked from a menu system and has the manual reference adjacent to it. It is listed in the component advisories where it can be selected and the worse that you could do is tick the dangerous box. If you did find a way to fail it, all it'll take is a post on a forum such as this, get a VT17 appeal form an inspection from VOSA and you'll have some disciplinary points. As mentioned previously, the test is to VOSAs standard, not yours or mine.

Going through the above, item by item. Brake pad breaking up, the tester isn't going to easily see that, when the pad is compressed against the disc when using the correct method of inspection - no dismantling allowed. Rear wheel cylinders leaking - if the fluid isn't low and can't be seen leaking between the back plate and the drum and with the above, the braking efficiencies measure up, the tester isn't going to notice anything amiss. Rear brake pipes corroded - a failure if the wall thickness is reduced by 1/3, at times difficult to assess due to the expanding nature of corrosion and position of the pipe. If it can withstand the higher than normal pressures exerted during the test without bursting and in the testers opinion is not excessively corroded, it's a pass and advise. Power steering pipe corroded, they have to be excessively damaged to fail - no mention of corrosion. Lower arm bushes, is there excessive movement?, 10% or more of their diameter if over 25mm in diameter, i.e 2.5mm +. Ball joint boots split - advisory, not a fail. This will be a fail from 01/01/2012. Rusty springs, their cross sectional area has to be reduced to such an extent that they are seriously weakened. Oil leak - advisory Rear sill corrosion, needs to be seriously weakened within 30cm of a prescribed area - suspension mount, seatbelt fixing etc. Cam belt due - maintenance item, not part of the MOT, though a refusal to test may be made, especially for a diesel. Brake fluid greater than 4%, assuming that this is moisture content. Level only is testable and that has to be done without removing the cap. It could be 100% water as far as the tester is aware. A lot of these items are not unusual for a 12 year old car and I should think that any competent garage could sort it all out for a lot less than £1500, barring the oil leak, whose cause is unknown. A MOT is not a guarantee of a cars future roadworthiness, reliability or condition, it just states that it met a set of minimum requirements at the time it was tested. The car is not tested to yours, mine, the garages or Joe Bloggs standards, it is tested to the standards laid out by VOSA. I'm sure that there are plenty of MOT testers who feel uncomfortable at having to pass something which they think is unacceptable, but VOSA don't. The Ford garage who checked the car post purchase was providing a service as requested, of course they are going to list everything that they can find with a view to getting some work.

The topic title implies that the actual test carried out on the car is suspect, further reading states that the MOT certificate expiry date has been tampered with. The certificate is no more than a receipt, the proof of a vehicles MOT status is the database entry. You will need the V5 registration document reference number to look up the computerised MOT history of the car. It seems fraudulent to me, would the Police be interested?, have you a copy of the e-bay listing?, even private sellers aren't allowed to be as dishonest as this. From September the MOT paperwork will be printed on plain paper, which, in my opinion, will make it easier to tamper with.

Too many people, without giving it a second thought, think that a MOT is report on the vehicles condition. It's not, it won't report on the state of the clutch, transmission, whether the bodywork has had repairs, the paint condition and a whole host of other things. On the advisory notice the tester gives an opinion as to what may require attention in the future, different testers will give different opinions. An important factor behind a tester issuing an advisory is to cover his back, should VOSA become interested in a particular test. The buyer can look at the certificate, see as to whether an advisory was issued, note down the test number and view the advisories over the internet. From September, it is likely to change when the testing stations go over to black and white plain paper printing. The certificate will be on one half of a landscape A4 sheet, with the advisories adjacent.

The MOT standard with respect to brake discs is very low, much lower than what would be considered as acceptable during a service inspection. If the pad thickness can't be assessed with the wheels on the car, then the tester can'r really comment of their condition. If your brake discs weren't wafer thin, cracked, have chunks missing out of them and not contaminated with grease etc, they'll meet the test requirements on condition. They can be as corroded and scored as you like, provided that they meet the requirements on the roller brake test or accelerometer test, they're acceptable as far as VOSA is concerned. With respect to the issue of advisory notices, there is a box on the certificate that says 'Advisory notice issued', which will have either a yes or a no in it. It could also be argued that the advisory notice is the property of whoever paid for the MOT test, so they don't have to give it to you.

You'll want the head checked for flatness and skimmed if necessary, crack and pressure tested, they might even have to strip it down to do this, that's the specailist cylinder head work. On an 8 year old car you can encounter all sorts of stubborn fixings which will add to the labour time, usually the 'book' times listed for the job are manufacturer derived times based on working on new vehicles. Even relatively minor sounding things like cleaning the cooling system takes time. No garage is going to warrant a cylinder head job without replacing the timing belt and you don't just replace the belt, you really need to do the tensioner and pulleys as well. It also seems that the auxiliary belt tensioner was suspect as well, which probably wouldn't have been in the original estimate. The difference between the estimate and the final invoice is basically the auxiliary belt tensioner, how many garages automatically estimate for one when pricing a cylinder head job?, not many I think. There was a report in one of the trade magazines recently where a garage had done a cylinder head job on a car, sometime later the car overheated due to a faulty radiator and the garage had to fix the car at their own expense. It was deemed that they were the experts and should have replaced the radiator at the time. Bear in mind that you have also given the Government £227. I think that it is the going rate for a good job.

You requested the garage to look at the fuel filter, they as likely gave it a visual inspection and checked it for leaks. Finding nothing wrong they reported it as OK. Now it transpires that the fuel filter connector is faulty, often there is a ridge on the filter pipe and the fuel hose has an integral snap on connector. It seems to me that the faulty part is the fuel hose. What part did the RAC say was faulty on their report?, or did they just note the symptoms of the breakdown, not the cause. It could have been a poor description of the problem that led them to look at the wrong component and they just followed your instructions.

Rental companies often use SIPP codes to identify various vehicle attributes. A Mondeo code should begin with I, what does your rental agreement/invoice state? If the Civic one begins with C then it's a group lower than the Mondeo. When I worked in car hire quite a few years ago we had both Mondeos (IDMN) and Civics on the fleet (CCMN).

That's the model of Scenic that is reknowned for having an instrument fault, so widely publicised, that Renault were offering out of warranty replacements for £100 parts and labour including VAT. We had one done on a Scenic that we sold shortly after the customer had taken posession of it. A complete new instrument cluster showing 0 miles, an invoice for £100 and nothing much in the way of documentation in the service record, would make the VOSA record plausible.

I think that you are getting me confused with someone else on this forum.

A spring is in compression all the time, whether the car is in use or parked up , it's always under load, so yes they can go at any time. How badly damaged was that corner of the car?, did the repair involve any dismantling of the suspension? Springs usually crack and over a period of time the crack gets worse until the spring fails. Is there any corrosion on the snapped faces of the spring to show that it has deteriorated over time? It's quite hard to accidentally break a spring whilst repairing another area of a car.

I don't think that any seller has to volunteer information about a vehicle without being asked a specific question. The only exception to this for a trader, is that they have to volunteer as to whether the vehicle has been an insurance write off. It is not an offence to alter mileage readings, the offence lies in stating or implying that the mileage is genuine when selling. The mileage could have changed because a faulty dash panel has been replaced with a used one. The mileage on the previous MOT could be an error, the trip mileage or even the last 6 digits of the vehicle identification number may have been entered and the owner did not check the details as advised on the MOT paperwork. The title says that the car is faulty, what are the faults?

Section 1.2 Additional stop lamps fitted and connected must be tested. Where extra lamps are fitted and there is doubt as to whether they are connected, the benefit of this doubt should be given to the presenter Section 1.7 & 2.1 (Which may be in the new manual for 2012) Where headlamp levelling or cleaning devices are missing or defective, but there is doubt as to whether they are required, the benefit of the doubt should be given and an advisory notice issued The inspection of the steering lock mechanism applies to all vehicles where it is fitted as standard by the manufacturer. If there is doubt as to whether a steering lock is was originally fitted, the benefit of the doubt should be given. Appendix C, 11 & 14 It is accepted that it is sometimes difficult to identify the repair method after the repair has been covered in paint or underseal. If the method of repair is in doubt the tester should pass and advise. If it is considered that a modification has significantly reduced the original strength and stiffness of the structure, the tester should fail the vehicle under the appropriate section. If there is doubt about the effect of the modification the tester should pass and advise. So hardly a case of the manual saying if in doubt fail it, more like if in doubt pass and advise.

No it doesn't.

The car could quite possibly be in need of new brake discs and pads even it has just passed an MOT. The tester can't remove anything to get a good look at them, whilst on a service they can remove the wheels to get a good look. The discs could have a good few mm of corrosion all over them and it can't fail an MOT on that. Provided that they haven't got chunks out of them, are not cracked, wafer thin or contaminated they can't fail. To be honest they have to be alot below a gernerally accepted service standard before they can fail a MOT. You can't really replace the discs and re-use the pads. With the spring it's possible that a part of it could be missing from an end, which the testing garage missed and it's good practice (not compulsory) to replace spriings and dampers in axle pairs.

Posts #1, #4, #6 & #8, say that the head gasket 'has broken', one source from the OP, another from the AA amd another from the garage that have the car.

Is it possible that you're all jumping to conclusions. The OP says that the coolant light came on first and that whilst on his driveway the coolant leaked out. It could be possible that the cooling system sprung a leak first either due to a fault or damage and the headgsket problem is a result of the lack of coolant, not the cause of it.

It could be more basic than that. Was the water pump changed at the same time as the belt?, we always recommend a water pump change and always use a cam belt kit. We even lost a job when the customer thought it was not necessary and got just the belt changed elsewhere for a much lower price, he came back to tell us. We saw him again a few months later when his car was towed in with an expired water pump, that stripped the belt and bounced the valves off the pistons. It's a diesel engine, compression ignition, which means that the compression ratios are quite high. The majority of lower compression ratio petrol engines are not 'safe', so I doubt that there are any 'safe' diesel engines.

How do you know for certain that the tester failed to inspect the rear brakes? The tester doesn't have the luxury of been allowed to remove items to effect a thorough visual inspection. For all we know the view of the brake components from the front through the wheel and from the rear could be extremely poor. The criteria for failing brake discs is quite clear, they can only fail for excessive wear if it is considered that they are severely weakened, they can also fail for being insecure or contaminated by oil/grease. Pads fail when the friction material is less than 1.5mm, if the tester can see them. It is not part of the test to measure the thickness of discs or pads. As part of the test the brake efficiency will be measured, usually by means of a brake roller test (RBT), the braking weight of each wheel will be recorded on the check list and entered into the computer, which will produce an efficiency calculated on brake testing weight of the car. Some cars are not suitable for a RBT and will have their braking efficiency measured by an accelerometer, which will give a reading for the braking system as a whole. So if you consider the scenario of the brake efficiencies above the the fail threshold and the tester not having an adequate view of the brake components, then the brakes have to pass, a car can't be failed just because a testable item can't be inspected. The 3 month window is for structural corrosion issues, passing a MOT doesn't guarantee that the car will work for 2 hours after the test, let alone two weeks. The issue is with the service, not the MOT.

It'll be a pressure sensor fault, but this sensor is an integral part of the ABS module. It is a common fault and VW do have a scale of goodwill contributions in place for this. A work colleague had this recently on her 3 year old 25000 mile Golf, as it had full VW service history they made a 100% parts and labour contribution. On the MOT, at worst an illuminated ESP light should get an advisory, the only warning lights that are checked are the ABS and the tell tales for the indicators and rear fog lamp.

From post #8 The 1 month owner could have had the mileage 'corrected'.