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My boss got a 1999 996 c4 because he liked mine son much. He is not a forum person though so I am asking on his behalf. I first tried searching but could not find another topic similar to this. Unfortunately my car is in the shop, so I could not compare. A strange noise is occurring when he is starting/accelerating or going around corners and the PSM kicks in. It is almost like a mechanical or growling sound. Everytime it happened, it was like his car was loosing traction. I told him I do not recall it making this sound before in my car. Is this normal? If not, what is the most likely problem?
TIA,
Mark
It is not normal, why is PSM even kicking in? While PSM is taking over is cuts thottle to the engine, and activates brakes, sounds like ABS. This doesn't sound like growling at all.
Could be a wheel bearing making noise.
If PSM is kicking in, are the tires properly fitted and in good shape, no mix matched sets, or worn out fronts and new rears.
It is happening when the roads are covered in snow while he is accelerating. The noise occurs at the same time the PSM light comes on in the dash. The tires are brand new (500 miles) and are a matched set. As this is a 1999, could it be the LSD making noise? It does sound like it is coming from the front. I did not think it was the wheel bearing as others have stated the noise is a like a constant whirring sound.
not all 99s have lsd and there's no way to tell if this noise is normal or not unless someone goes on a drive with him. has he taken it to the porsche dealer?
Are you kidding? Roads covered with snow and accelerating in a 300hp car - of course the traction control / PSM kicks in; even if he has snow tires. What car did he drive before the 911? He needs to be very gentle on the gas on snow to have PSM not kicking in.
Of course he needs to take it easy when accelerating that was the answer to Jumper who asked why is PSM kicking in. He was in an empty parking attempting to have some fun this morning when he heard the noise. No he has not taken it to the dealership yet.
well could be the noise of the front diferential working. Once the rears lose traction the power is sent up to the front.
While I am losing tracking with PSM on, the throttle is cut and you can hammer it but it doesn't do anything. The car then controls the amount thottle and your hear mechanically clanking as it brakes the individual tires that are slipping. It feels like your grip is coming in spurts.
The situation you described is exactly what is happening as I drove it too so I could understand what he was talking about. So is this mechanical clanking normal?
Thanks again. I did not know the PSM noise was normal when it kicks in. Once again, it is nice to have a group to ask questions to who are willing to help out fellow owners. I told my boss & let out a huge sigh og relief upon hearing this news. He was upset & thought the new (to him) car was already having issues.
spaceman send you boss here to Rennlist and have him introduce himself so we can give him something to worry about. We'll tell him about RMS leaks, grenading engines, leaking coolant tanks, faulty ignition switches, seat belt connectors that go bad, etc., etc.!
Just kidding!
PSM was kicking in for me on one turn in a way that made
me wonder if it wasn't working correctly.
It tried it several times through there, and then turned the PSM off
and did it again.
Is had been working. And I had my hands full for a moment. ;-)
Bill
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