2001 V70 STC problem..MVSOLVED rear caliper hang up

altalake · Post by **altalake** » 08 Jan 2015, 22:52

2001 V70 FWD 5spd Manual transmission has developed an issue which seems to be related to STC. In normal (STC enabled) mode, the LF wheel assy will produce a scraping/grinding noise on a low speed hard left turn (ie: when the left wheel is turning slower than the right). The STC dash light will flicker when this is occurring. This happens on wet or dry roads, bare or snow covered, accelerating or steady speed. It pulses on and off in cycles a couple of seconds long if I keep it going in a circle.
It's the same noise as when STC engages when starting on ice. It's a goddawful noise for anyone who's never experienced it but it is normal when the STC is doing what it's supposed to do - which is to engage a brake on a spinning wheel.
With the STC disabled there is no noise. No warning lights. According to 2 shops this is not a known issue. Any ideas?
btw, this car does not have DSTC, just STC.

Post by **jimmy57** » 09 Jan 2015, 09:35

Remove the wheel and then look behind hub and follow the black electrical lead to the sensor. Undo the bolt and remove and inpect the sensor. Look at tip for evidence of contact or for collected metal "fuzz".
My suspicion is the wheel bearing there is failing.

You mention no warning lamp and that would seem to indicate that the electrical part is good and only the signal created is erratic or missing at low speeds and in turns. When signal issues occur at low speeds the diagnositics are not as likely to detect it as take off and cornering wheel spin is common and being too sensitive would set codes every time it rains or is icy.

altalake · Post by **altalake** » 09 Jan 2015, 10:18

Thanks. Will check and post what I find.

altalake · Post by **altalake** » 10 Jan 2015, 14:51

Solved - at least for now. RF brake caliper was dragging - and dragging worse when turned to the left. This makes sense since the anti-spin circuit would see this as the opposite wheel spinning and it only happened at low speeds - not dragging significantly when up to speed.
I must have been wrong about this happening on a bare, dry road. In retrospect, I probably haven't seen a bare, dry road in a couple of months.

altalake · Post by **altalake** » 23 Apr 2015, 22:06

Issue returned and no longer required slippery roads to show itself. Likely cause discovered: broken tone ring (aka reluctor or pulse ring) right side front.