My Audi A4 recently developed a fault that caused the ECU to switch to ‘limp home’ mode under various driving conditions. I took the car to an Audi dealer to have the fault diagnosed – at a cost of £90 – and was told that the variable vane geometry turbo actuator on the exhaust side of the turbo was sticking. Audi quoted £1200 + VAT for a new turbo + labour

I didn’t want to pay Audi to fix the car so I carried out the work myself and reconditioned the turbo and refitted it. Exactly the same faults were experienced following the work and I later found out it was either the EGR valve or Lambda Sensor at fault. Can I take action against Audi for giving me the wrong fault diagnosis?