Can anyone tell me what the sensor marked by number 11 is for? It is on the lower control arm. Part number is 99134392180 and is labelled suspension ride height sensor, but what does it do? I've been told that it is for the headlights?

 

Yep,that's what it looks like...

 

It's part of the PDLS. Not sure exactly how the mechanism works but it adjusts the headlights aiming up and down. Not sure about the GT4 as I haven't looked in the back but my 987.2 CR has similar sensors on the left front and also on the left rear LCA. I damaged the rear one on track and the headlights pointed down drastically limiting the range of the lights. Made night driving unsafe until repaired.

edit- I just poked around under both the CR and the 4, on the CR there are sensors only on the left side. On the GT4, it looks like there are sensors at all four corners. I wonder if the signals have some input to PASM? Of course the CR is non PASM. So not sure I helped any on your question!

 

Yeah, I thought it was for pdls, but I don't have pdls on my car and the sensors are still there. The reason I ask is that the rss monoballs don't accommodate these sensors

 

Are you switching to all RSS now from Tarett?

 

Yes

 

We have RSS standard length brackets for both front and rear sensors and will be releasing the XL monoball brackets shortly. I will PM you with the details.

 

Thanks, Mike.

 

These ride height sensors, front and rear, are for any car with Xenon lights, which the GT4 has even if no PDLS. PDLS only steers left/right. For the Xenon headlights to be legal in US, they must have capability to aim the beam up/down to prevent dazzling oncoming drivers with different ride attitudes of the car.

I think you'll find a version of this on any car with the HID or Xenon headlights.

 

Thanks, okie!

 

Glad to help. I think the worst that will happen if you remove the arms and fix the potentiometers in place is the headlights will be fixed in aim up/down.

EDIT: 22 March 2017, see this post: https://rennlist.com/forums/gt4/9816...l#post14056608
The GT4 uses these sensors, one at each corner of the car, to send pitch/roll inputs to the PASM control unit. My original posts in this thread were based on thinking there were only 2 sensors, 1 front and 1 rear.

 

Same properties as a Low Range Radio Altimeter

 

Lets you know when one of the front shocks has blown through the strut tower.

What, too soon?

 

lol

 

When I installed X73 in my CS, the dealer left this unplugged. Took them a few hours to figure out what the problem was and then had to drop the subframe all over again to plug them back in.