For you to be able to pass the driving test with a private car, your vehicle must pass the basic visual inspection conducted by the DSA driving examiner.
Every week I either see or hear of driving test candidates who come in their private car being denied the chance of taking the practicar car assessment because their vehicle does not have road worthy tyres, a large crack on the windscreen or the headlights are not working properly.
All the requirements that your private car on the driving test has to fulfil are listed on the DSA driving test appointment letter sent out to all candidates, so check your car at least a day before the test, and get any defects fixed before going to the test centre.
You will lose your fee, if the test can not go ahead due to a problem with your car, and at £62 (April 2009), that could be a very expensive mistake!
If at all possible I would always recommend you use a driving school car, though you can expect the instructor would like to make sure you will not crash his vehicle by asking you have a couple of lessons before your test date, but you will not have any cancellations of test by the DSA examiner if you hire a driving test car using this method.
How much do guaranteed test pass courses cost?