Valhalla
Member Since: 23 Oct 2011
Location: Isle of Skye
Posts: 124
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| Steering Angle Sensor slight misalignment |
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09MY D3 HSE, 19" rims with new Pirelli Scorpion tyres
Had a strange one just before the weekend; The car drove fine until it got onto faster A-roads, then would kick the DSC into play whilst cornering at circa 65mph in shallow bends. I guessed what it would be before I took it out, but it surprised me all the same. As well as the DSC coming into play during the corners (left and right), the car did genuinely feel unsettled. By D3 standards, it felt awful.
Found that as well as the SASM drive dog being loose on the steering column by +/-8degrees, which meant that the steering angle was erratically stuck in the wrong direction about the straight-ahead position, there was also a front wheel toe-out misalignment by about one-and-a-half degrees towards toe-in, although no indication that this had been adjusted recently. The SASM calibration was pretty well spot-on at 0degrees steering angle, so the dog was just slipping back and forth within a small range.
The combination of the two faults above meant that the lateral-G and yaw sensors were reading a car that was a bit skittish, but in combination to this, the steering direction was lagging in the wrong direction as the car turned in to the bend. Once fixed, the car drives like it should again.
This is the first time I've come across the SASM drive-dog causing problems during the early stages of failure (rectification was usual epoxy-fix between dog and steering column), as the common problem is the 15mph full-blown Special Functions failure when the dog slips more easily.
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 10th Mar 2014 1:15 am |
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