GrahamB

I have a 2004 V w/ 42k mi on it. This jerking issue came on all of a sudden a few months ago and I have been trying to figure out the problem. It only happens during acceleration, it only happens at between 83-87mph, and it is never on conjunction with brakes being applied. It has happened during somewhat aggressive acceleration and it has occurred during slow acceleration. When it happens the car suddenly dives to the right, the front tire locks (tire screeching), stability control pops on, and car jerks back to control. It seems like the massive jerk and stability control popping on occurs simultaneously although the first two times I could have sworn that it was an after effect of the actual jerking/screeching and didn’t pop on until after the episode began.

It does not happen every time although as far as I know the car has only gone above that threshold (and only by a few miles per hour) 2 or 3 times since this reared its ugly head. I have taken it to the dealer and they have performed their fine toothed comb over of it and found nothing wrong with it what so ever. Their ONLY solution to why it was occurring, and a solution they were 100% confident on, was that I am running 245-45-18s in the front and 275-40-18s in the rear……which frankly is a cop out answer because they didn’t have a flippin clue.


This has taken all of the fun out of the car and frankly I don’t feel safe driving it.

Thanks,

Graham

joehernandez86

iTrader: (1)

I have had the same thing happen to me while i was going 140+ down interstate thought i was a goner for sure. I thought mine did it because while driving there was a slight bump i hit and thought it might have messed with stability control. Since then have not been over 110 haha. I would say it has something to do with your wheel speed sensors, the car may be thinking your losing control if there is a bad wheel speed sensor throwing a different speed.

DirtyDirk

Technician can drive the car with the tech 2 connected. Apply the brakes and check if a speed sensor is falling out sooner than the others.

GhettoTy

iTrader: (2)

It's a speed sensor, happened to me too. When I would hit a bump it would turn on traction control and cut power. It's dangerous and you need to get it looked at. Luckily for me it never happened on the freeway so I was able to control it.

JJSimon904

iTrader: (8)

Your back tires are shorter than your front tires. That will set off the traction control at high speeds (mine does that). The fix for that is turing off TC when you want to go that fast. But that isnt your problem. If it were the other way around(back tires taller than front tires), I would agree with your dealer as it would cause the stability control to do some funny things.

I'm guessing wheel sensor or something like that.


My 97 Camaro's ABS would randomly decide that the car was sliding so it would pump the brakes even under normal dry weather braking...well when that happens you dont stop even if you are standing on the brakes. I wound up in the middle of several intersections. I got good at using the e-brake. I traded it in on an 01 fbody after it caused me to have to put the car in the ditch (at 20mph) to avoid hitting someone. :

AAIIIC

iTrader: (19)

Can you do the math and tell me how you came to that conclusion?

siggyfreud

iTrader: (1)

Front tires are 245/45/18: 245/25.4 = ~9.646 * .45 = 4.34" in sidewall height

Rear tares are 275/40/18: 275/25.4 = ~10.82 * .40 = 4.33" in sidewall height

Both rim sizes are the same. In total, the fronts would be .02" taller in total if I did my math correctly.

LS2duc

iTrader: (1)

I bought my 06 6 mos ago with just under 4K miles. Really haven't "driven" it, just to prove wheel hop is for real (and it is). Sat night I took it out on a 20 mile stretch between Northampton MA and Vermont border. Cranked her right up to 145 indicated-no scary **** like you guys are describing. The sunroof got kinda noisy, but I repeated and think the sound is actually coming from the outside (no air escaping in). The previous owner insisted he never went over 100 and if you met this guy you'd believe him! I guess my mileage is just so low none of the mysterious things have happened yet. My V gets Maggie, headers, harmonic balancer, hendrix axles/CVS and UUC shifter this week. Bet some interesting things will happen then...

JJSimon904

iTrader: (8)

ding ding ding ding we have a winner!

SilveradoSS500

I had that happen at 168 in the Z. I triggered a sensor for sure, then I realized I didn't have my back right fender liner in which created lift! I almost lost it...

Make sure to turn everything off when you are going that fast.

Before I would even leave my parking spot, I hold for 7 seconds :-)

GrahamB

Thanks for the replies everyone. Given the responses it sounds like speed sensor......I assume this is a dealer only job??? Any idea on price? Is there any official write up (service manual?) or bulletins from Cadillac that I can reference when I take it back to the dealer to give them a clue how to test? Heck even a good write-up online would be better than nothing. Given my prior experience I may have to draw them a diagram of how to fix my own dang vehicle.

Thanks again,

Graham

GrahamB

This makes me want to go kick the dealership in the nuts even more. They were pushing for me to buy two new tires, through them of course, for the lovely amount of $900. I told him he was full of $hit and exactly where he could stick those tires. Too bad this is the only Cadillac dealership near here. Do I dare take it do a regular GM dealership?

Graham

aurora40

iTrader: (1)

That is 1/100th of an inch of tread difference. That's less of a difference than a typical tread depth gauge can measure. I would bet most people with 245/45's all around have more of a diameter difference front to rear than that due to uneven wear.

aurora40

iTrader: (1)

If you really dislike the dealer approach and you don't mind doing it yourself, you could just take a guess and replace the driver's front wheel speed sensor. Or the whole hub assembly if they aren't too pricey and that seems easier.

But I imagine the diagnosis would be difficult without a Tech-2.

AAIIIC

iTrader: (19)

Or make sure you actually have your car properly prepared for going that fast, in which case the electronic nannies will remain completely invisible until something is wrong.

Because you never know when you might need to drift the car through a school zone!

The wheel speed sensor is integrated with the hub/bearing, so it can't be replaced separately. It's a very easy swap, but the hub/bearing assembly ain't cheap.

It's just a car. I could be wrong, but I'm pretty sure any GM dealer will have access to the same GM service database that a Caddy dealer has.

As for your problem, I had a bad wiring splice repair that resulted in intermittent wheel sensor problems. The wiring had apparently been "repaired" at some point before I bought the car - I'm not sure what the problem had been, but the wiring had been repaired with the standard cheapo crimp-on butt splices. Worked fine for a couple years, then at a track event weekend I started getting intermittent ABS faults and/or Stability Control faults. Went most of the track event with no ABS, which was something I haven't done in a while. Anyway, the tech @ Lindsay found the old repair and said that although it was technically repaired per the service manual, whoever had done it hadn't done a very good job crimping the butt splices, and it finally resulted in intermittent contact.

So, moral of the story is I would have the tech connect the Tech2 box, then have someone under the car grab each wiring harness and move it around and see if there's any sort of intermittent ground/short.

greddy91

iTrader: (2)

... I think I recall something like a central yaw sensor under the center console...

Anyone?

GrahamB

Just spoke with the service advisor (who of course remembered my issue) and discussed different sensor possibilities with him. He kept insisting and jumping up and down it was tire size and that tread + difference in tires size = this problem. Eventually when it was obvious that I thought he was full of S*** he told me to go get my receipt, call GM, and talk to their technical center so they can deal with me. He also stated that his tech spend "a lot of time" testing different sensors and at different speeds/accelerations including the hub bearings (which I took as them checking speed sensors).

Graham

greddy91

iTrader: (2)

FTW:

https://ls1tech.com/forums/cadillac-...y-control.html

Yaw Sensor was a common issue with our bastard cousin Vette's also... Seems liek there is a for sale thread about a pick-a-part car in Arizona... might be a prime time to save some cash and fix your issue.

GrahamB

I was trying to avoid throwing parts at the car to test theories but ebay has used ones for $55 so its not bad at all. Also lots cheaper than the sensor hidden in the wheel hub bearing.

Is this literally a plug and play replacement? Just get the console out and go at it?

Thanks,

Graham

greddy91

iTrader: (2)

You're asking the wrong cat... I haven't totalled my V out yet with this stupid sensor issue, but I drove a Vette back in the day that exhibited the issues and the dealer never fixed it... The owner is now a BMW fan for life. Pretty sad.