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Discussion Starter · #1 ·
Thanks to Beernose (I think) for investigating the wiring in another thread a few months back.

We pulled the hidden F7 ABS pump fuse (pink 30A front fuse box) on my friends S40 AWD. The dash displays that DSTC is disabled. Further, full throttle acceleration is discernibly smother and more consistent on dry pavement with non performance tires. If the ebrake is pulled up one notch to disable the Haldex as well, the T5 will light up the front tires very easily with no electronic nagging or flashing lights! Note that this is just a lightly modded S40.

Next we plan to install a switch and a relay to toggle the DSTC off during autocross.

DISCLAIMER: Pulling the F7 fuse will also disable ABS too since this is the pump power connection, so this is for off road use only. You are responsible for the additional risk caused by disabling any safety systems on your car. This trick is intended for off road use only.
 

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I might have to try this tonight see if it makes a difference. Is this in the fuse box in the engine bay under the glove box ?

Why does the haldex disable with the ebrake trick and what does that do just transfer more power to the front?

"Embody god... Then go crazy"
 

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Discussion Starter · #3 ·
Yes, the fuse box in the engine bay. See below. Be sure to pull F7 and not F8. F8 will give you an immobilizer message. FYI when you re-install the fuse the system will reset after the car is driven again next restart. All will be restored to normal.

On dry pavement with the AWD there is not a huge difference. In first gear in really tight turns you may notice the car has a bit more ooomph. Be careful the rear will step out and he ECU will not help you sort out the slide.

The Haldex ebrake trick seems to be to protect the drive train. It even mentions this in some volvo literature.

 

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Yes, the fuse box in the engine bay. See below. Be sure to pull F7 and not F8. F8 will give you an immobilizer message. FYI when you re-install the fuse the system will reset after the car is driven again next restart. All will be restored to normal.

On dry pavement with the AWD there is not a huge difference. In first gear in really tight turns you may notice the car has a bit more ooomph. Be careful "the rear will step out and he ECU will not help you" sort out the slide.

The Haldex ebrake trick seems to be to protect the drive train. It even mentions this in some volvo literature.

"the rear will step out and he ECU will not help you" sounds like fun to me!


"Embody god... Then go crazy"
 

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Great to know! I wish there was a way to just perminently disable DSTC and not ABS. I miss the button in the S40... The wheel on the turn signal stalk is annoying.
 

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Discussion Starter · #6 · (Edited)
Great to know! I wish there was a way to just perminently disable DSTC and not ABS. I miss the button in the S40... The wheel on the turn signal stalk is annoying.
The wheel menu and button don't fully dissable DSTC. Nor does the push button in models that have it equipped. Only a portion of it.

FWIW pulling the fuse still allows the electronic brake force distribution function to work.. I have confirmed that the solenoids still function with the ABSENCE powered ABS pump.
 

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The wheel menu and button don't fully dissable DSTC. Nor does the push button in models that have it equipped. Only a portion of it.
That's what I thought all along... But do you know to what extent? I can do front wheel burn outs all day long with it disabled. It'll flash at me and immediately say that DSTC is unavailable, but nothing seems to change.
 

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Discussion Starter · #8 ·
Yes, the disable function on the DIM or the button only turns off the front wheel traction control. It does not turn off stability control. I.E. allows the front wheels to spin without pulling timing or backing off the throttle. However, the ECU still intrudes particularity on AWD models where the rear end would be trying to spin around on slippery surfaces or at autocross where you need oversteer in certain situations to improve lap times.
 

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Just autocrossed last weekend and I didn't find yaw control to be an issue (which surprised me). Plenty of oversteer with a large rear sway bar.

We need to find a way to disable yaw control and keep ABS. Anyone unplugged the yaw sensor yet? That was my plan if it gave me issues at the autox....
 

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Is it hard to get the AWDs to oversteer? I can swing the back end out on just about any turn (though, my suspension is super stiff), I actually have to be careful in the rain not to get too tail happy.
 

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Discussion Starter · #11 ·
Yes, with all the driver aids on I have never been able to get to full opposite lock. The computers shut it all down way before it gets fun.
 

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i never had any trouble sliding around in the snow. It was rare for a light to ever come on for me while in the snow... but maybe there isnt much g-force when sliding on snow? so sensors dont detect anything wrong?
 

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Why couldn't this thread been around a month! Will take note for future reference.

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This should be a sticky!


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I was on the track yesterday and altho I had the dtsc turned off, I had a warning message come up saying that traction control temporally off display after about 2 laps.

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I was on the track yesterday and altho I had the dtsc turned off, I had a warning message come up saying that traction control temporally off display after about 2 laps.
If you can make the light flash for ~10 seconds non-stop (skidding around a lot), it'll do that. Happens almost every AutoX and dragon run I do.
I'm not complaining. :D
 

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The car was a lot nicer to drive with it off...

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I was on the track yesterday and altho I had the dtsc turned off, I had a warning message come up saying that traction control temporally off display after about 2 laps.

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Mine only did that when I did an evo school and overheated the brakes


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Found a thread on here and a xc90 manual online that says it's because the brakes are too hot... Hahhaa

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Sounds about right


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