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Is my TRACS-system broken?

Help, Advice and DIY Tutorials on Volvo's P80 platform cars -- Volvo's 1990s "bread and butter" cars -- powered by the ubiquitous and durable Volvo inline 5-cylinder engine.

1992 - 1997 850, including 850 R, 850 T-5R, 850 T-5, 850 GLT
1997 - 2000 S70, S70 AWD
1997 - 2000 V70, V70 AWD
1997 - 2000 V70-XC
1997 - 2004 C70

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SomeGuy537
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Is my TRACS-system broken?

Post by SomeGuy537 »

Hello, i have TRACS in my 850 but i'm not sure if it works. I have turned the system on with the button on the dash but haven't felt it doing anything in slippery conditions. It might be that i'm driving so carefully that the system doesn't need to activate though. However the TRACS-light in the instrument cluster lights up as soon as i press the TRACS button? Is this normal? In my manual it says that this light should never be on while driving and that it indicates a fault. The TRACS-light goes off immediately when i turn TRACS off again. The strange thing is that my ABS works perfectly. As i've understood it, TRACS is just a software extension of the ABS hardware. It applies the brakes to one of the front wheels if it starts spinning and thus drive force goes to the other wheel right? I have a fault code from the diagnostics system though and it is "4-2-4" and the description is "Pressure switch for TRACS faulty or short circuit."

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misha
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Post by misha »

Tracs is always ON by default.
When you press the tracs switch and light "Tracs Off" appears on the cluster....it means what it says....tracs off.

I don't think that something is different on earlier models.

What i wrote above is for '96 and later models and that's how light appears on the cluster.

When abs system detects a fault...tracs is inoperative too and both...abs & tracs off light appears on the cluster.

Edit:
Lee says that on early models it works different way:
viewtopic.php?t=25521
'97 850 2.5 20v / fully equipped / Motronic 4.4 from the factory / upgraded with S,V,C,XC70 instrument cluster / polar white wagon
History of Volvos in the family:
'71 144 S
'73 144 De Luxe
'78 244 DL
'78 244 DL
'79 244 GLE
'85 340 GLS

SomeGuy537
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Post by SomeGuy537 »

misha wrote: 20 Jan 2021, 08:19 Tracs is always ON by default.
When you press the tracs switch and light "Tracs Off" appears on the cluster....it means what it says....tracs off.

I don't think that something is different on earlier models.

What i wrote above is for '96 and later models and that's how light appears on the cluster.

When abs system detects a fault...tracs is inoperative too and both...abs & tracs off light appears on the cluster.

Edit:
Lee says that on early models it works different way:
viewtopic.php?t=25521
Mine is a 94' and when i push the TRACS button i get a light in the instrument cluster that simply reads "TRACS" and nothing else. I've checked the manual and there's nothing about a "TRACS OFF" light. Perhaps that only exists on the later model years.

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abscate
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Post by abscate »

1994 850mowners manual entry
A - TRAction Control System (TRACS) - option

TRACS is a system designed as an aid when starting/driving off if one of the drive wheels has poor traction due to weather conditions or the road surface and is connected to the ABS control module.
TRACS is switched on manually with a button on the dashboard. The indicator lamp in the button will light up when the system is ON. With the button in the ON position, TRACS activates automatically if one of the front wheels loses traction, shifting power to the wheel with best traction. A sound from the ABS control module may be audible at this time. The system functions only at speeds under 25 mph (40 km/h).
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Clemens
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Post by Clemens »

TRACS is barely felt compared to modern Traction Control systems. My Turbos spin the wheels if I want to, no matter what TRACS does. I can hear it working, though. It kinda sounds like winding up a spring in a windup car.
Summer: 1996 855 R
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BEJinFbk
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Post by BEJinFbk »

As mentioned, you should at least be able to hear it.
On my ‘98, it’s pretty noticeable. Kind of a cross
between a giant rogue hard drive and a very
excited squirrel that got ahold of some meth.

Also worth mentioning that it only engages
at under 25 mph.
Last edited by BEJinFbk on 21 Jan 2021, 22:50, edited 1 time in total.
'98 V70 R - Well Equipped for Life Up North... ;)

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abscate
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Post by abscate »

In 1999, the electronic throttle allowed electronic torque control of the motor so we got STC.

IN winter, it’s great. You can drive until STC starts to activate fir wheel slip, then back off 5-10 mph and drive without slipping. It’s about twice as sensitive as I can detect by “ road feel”
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Clemens
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Post by Clemens »

BEJinFbk wrote: 21 Jan 2021, 19:21 Kind of a cross
between a giant rogue hard drive and a very
excited squirrel that got ahold of some meth.
😀😀😀
Summer: 1996 855 R
Winter: 1994 855 T5M
Donor: 1995 854 10V

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abscate
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Post by abscate »

BEJinFbk wrote: 21 Jan 2021, 19:21 As mentioned, you should at least be able to hear it.
On my ‘98, it’s pretty noticeable. Kind of a cross
between a giant rogue hard drive and a very
excited squirrel that got ahold of some meth.

Also worth mentioning that it only engages
at under 25 mph.
Missed that one, it’s keyboard sploogable!

:D :D :D
Empty Nester
A Captain in a Sea of Estrogen
1999-V70-T5M56 2005-V70-M56 1999-S70 VW T4 XC90-in-Red
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