Car displays various intermittent messages. The most serious is "Drive System Failure" (followed by other sys messages) as car then goes into low-power safety mode. Audi dealer has so far a) installed various software updates - none worked as a more recent audi-requested update was soon followed by another sys failure/safety mode plus intermittent 'aileron' noise with each gear change. b) wire from "pin 4 to engine" replaced by Audi dealer. Only temporary relief as failure noted in a) occurred soon afterwards. c) Audi dealer has replaced a sensor ( for fuel pressure! ?) claiming that the sensor malfunction had been the cause of all the previous system failure issues. I am dubious - upon asking how come a malfunctioning sensor had not been detected in over 2.5 years of their trying to solve the issues, I was told "that's a good question". I suspect that as the software patches, wires (and now possibly?) sensor have not eradicated problems, I'm inclined to suspect that these items are more symptomatic rather than causal. The latest but chronic display irregularity shows intermittently upon switching off engine/ignition: display lights up with message "please switch on ignition to configure selected system" and repeats even after obeying said instruction. To my mind all these are at least suggestive that Audi should be looking into possible root cause(s). Could it be a faulty e.c.u. computer hardware component failing to configure system, eventually leading to failure of stressed parts? I don't have an answer. Any suggestions / comments would be gratefully received.
