Bump and oldish post, but useful for others perhaps? The grinding (or for some cars, a spring-like sound) is activation of the ABS. The 'usual' cause for the ABS to activate whilst no wheels are locked is a faulty sensor. In my experience, for this to happen (Note: NOT necessarily YOUR issue): Notes from experience: - The sensor is 'electrically' fine - i.e, the ABS ECU can detect it and it's within tolerance. - The sensor 'may' return a valid signal whilst the wheel is turning (likely weak, but enough to trigger valid in usual diagnostic). - Diagnostics happen when things are cool or cannot get hot unless driving. Other causes, likely or unlikely: - Water inside ABS sensor connector. - Metal filings on ABS sensor (They are magnetic). - Sensor ring loose. - ABS sensor ill-fitted. - ABS sensor fails (completely or intermittently) when the hub becomes warm/hot. Personally I have: - Caught the ABS sensor lead, causing intermittent connection - failing on heavy braking. - Bent the ABS sensor. - Coated the sensor in metal filings when repairing or cleaning areas around the hubs. I have also similar experience with the same type of sensor (flywheel position sensor) with the above issues (heat causes failure, water in connector) and metal filings. How repeatable is the issue? Hot day, wet day, both? X hours driving? The very least, is the dealer should lend a replacement set of sensors - maybe in pairs to track the axel at fault. I'm unsure if the ABS ECU can be interrogated for last wheel that has loss of traction? Hope you get it sorted, but also post back your current situation.
