Hi John. The price to start with is an unknown quantity as you have to find out what is wrong with it before you can fix it. ( £45.00 per hour for as long as it takes to diagnose and fix the problem )

i usually say how can i give you a price before finding out whats causing the problem and what it requires to fix it. ??? it might simply need a service, a £5.00 component, or an Ecu or an engine to rectify the problem. which could range anywhere from £50 to £2500.

i would say that you need 1 hours labour to code read the vehicle, do an emissions test and an initial assesment.

at that point you will have either identified a problem or found out that you need to go deeper and then you can advise the customer what you think the next step is. ( either further investigation at your hourly rate or may need some parts fitting )

Even after you have identified a Faulty component, you cannot tell the customer that it will definitely fix it, ( All you can say is that part is faulty and it will not pass an mot untill its replaced so it has to be changed ) as it might bring the emissions readings down from 10% C0 to 2% C0 but it will still fail the test, so will then need more time and parts.
( i,e, it could have damaged the cat or contaminated the oil etc etc )


If they still don't understand, they can let the other guy fix it or do it themselves.