Thread: Question regards TC

1. Yes
2. That is normal. There is a pump in the ABS Modulator that runs when the TC is active* which makes this noise.

So nothing to worry about.

cheers
Paul

* RAVE refers to this as "active braking mode".

Active braking mode
When ETC or HDC are enabled, and the SLABS ECU determines that active braking is necessary, it starts the return
pump. Hydraulic fluid, drawn from the reservoirs through the master cylinder, shuttle valves and lines 'B', is
pressurised by the return pump and supplied to lines 'A'. The SLABS ECU then operates the inlet and outlet solenoid
valves to control the supply of hydraulic pressure to the individual brakes and slow the wheel(s).

Everything quite normal there. TC works irrespective of whether in hi or lo and like ABS activation you will fee vibration through the brake pedal and hear the "grating sound" that is all normal - applies to all cars with ABS and TC.

Garry

Yes, TC is on all the time, in both Hi and Lo range. I'm not sure about the 'grinding" noise. You can definitely feel it and the orange TC light will light up on the dash. Come to think of it, I guess it does make a 'grinding' noise'. It certainly isn't a subtle noise that's for sure.
Offtrack is the man for all things related to SLABS, ABS Ecu's.....


Dave

Thanks for the answers guys, and I am happy that it is normal.

Just not used to a "grinding" sound. To me, Grinding noises usually mean trouble. But that is one I wont have to worry about.

Thanks for the quick responses.

That noise also had me worried when I first went bush in my D2. Luckily I had an experienced D2 owner with me and said it is normal. The car tries to pre-empt that you are about to loose traction and fires up the compressor ready to go. You get used to it after a while.

Originally Posted by Landover

The car tries to pre-empt that you are about to loose traction and fires up the compressor ready to go. You get used to it after a while.

That is a very good point! I've also noticed that often the pump runs without the ETC light coming on.

The ETC actually allows a wheel to spin faster than the average of all four - in the range of 5-10% faster. I guess what is happening is that the ETC is detecting a wheel getting close to that slip threshold and activates the pump, but the wheel has sufficient grip that it doesn't reach the point where ETC actually starts braking wheels.

If the ETC activates the dash light should stay on for two seconds. I was surprised by the number of times the pump runs but the ETC light doesn't actually come on.

cheers
Paul

Originally Posted by mattadelaide1975

Thanks for the answers guys, and I am happy that it is normal.

Just not used to a "grinding" sound. To me, Grinding noises usually mean trouble. But that is one I wont have to worry about.

Thanks for the quick responses.

HDC is another one that really gives the ABS Modulator a work out.

You can test it out on the flat. Shift to low range, engage HDC, then accelerate up to 20-30kph and take your feet off the brakes and accelerator.

Another "interesting" thing to try is driving tracks with HDC engaged. The accelerator modulates the HDC target speed up to 50kph. When you lift off the throttle HDC will start progressively braking to slow the D2 down to 7kph, so you can actually drive without physically touching the brakes. It's not something I'd do that often but it is useful to explore the way these systems have been designed every now and then. It's kind of handy to know that you don't need to just switch HDC on at the top of a hill then off at the bottom

Originally Posted by OffTrack

HDC is another one that really gives the ABS Modulator a work out.

You can test it out on the flat. Shift to low range, engage HDC, then accelerate up to 20-30kph and take your feet off the brakes and accelerator.

Another "interesting" thing to try is driving tracks with HDC engaged. The accelerator modulates the HDC target speed up to 50kph. When you lift off the throttle HDC will start progressively braking to slow the D2 down to 7kph, so you can actually drive without physically touching the brakes. It's not something I'd do that often but it is useful to explore the way these systems have been designed every now and then. It's kind of handy to know that you don't need to just switch HDC on at the top of a hill then off at the bottom

Is it possible you could use HDC in situations with slippery mud?
Last time I went out to ophir, being the arrogant teenager I am, tried a track marked dry weather only about a day after heavy rains
Slight incline, wouldn't have been doing more than 20km/h, heading towards a sloped choke point (trees either side of the tracks) and a dab at the brakes and had zero brakes and minimal steering at best.
lots of fun
And yes, I'm aware I shouldn't have been there in the wet, at least without muddies