clashmin

the warning light comes on randomly- no other lights come on- all different RPM's and temps. Anyone have any ideas?

Dunasso

Hi,

I'm not sure what the exact purpose of the light is for, Maybe a general alert. I had a simillar problem with my car a few years ago and it turned out to be the O2 sensor. There is no local Porsche dealer in my area so I called a couple of import shops and it was recommended to replace the O2.
It was very easy to get to, upon removal of the heat shields on the catalitic converter. The plug is located in the engine compartment behind the electric blower on the left as you are looking at the engine.

I hope this helps, however you may want to have it looked at professionally. It was all that was needed for my repair, as I haven't had the light come back on sence, for the exception of initial start up, which I am told is normal.

Duncan

garrett376

Make sure all of your other warning lights DO come on when you first turn on the ignition (I posted an image a while back showing these). That will confirm that you have no other bulb that's out. My reasoning: you could have another bulb that is burned out, and you just see the big exclamation mark warning light, although another light should be on too, telling you what's wrong. My understanding is that the exclamation mark comes on in conjunction with another light - not by itself.

I'd start there! It's easy - turn on your ignition, make sure everything lights up... if it does, then you start looking for something else...

Here's the link I mentioned before:
https://rennlist.com/forums/showthre...warning+lights

clashmin

now, once in a while i hear a loud buzzer- what is this car trying to tell me?
thanks for the other info-

Adrian

How long have you had the 964?
What version, model year of 964 do you?
Which warn light are you talking about?
The fact that you mention the warn horn I assume you are talking about the master warn light (!). This is telling you that you have a priority one failure. However seeing as I have no idea what 964 we are talking about theonly thing I can say is that the PO has most likely pulled the actual warn lights of a problem withthe 964 and sold it on.
The first thing you do is pull out your owners manual, turn the ignition to "ON" and check that all the warn lights that should be installed for your model, model year and version are illuminated.
Ciao,
Adrian
964C4

Adrian

Okay I see by your other post now who you are.
C4, I bet the PDAS and ABS warn bulbs have been removed. You can check this easily. The PDAS and ABS lights should be on when the ignition is turned on. The ABS should go out and the PDAS remain on with the brake pressure warn until the hydraulic pressure has reached a specific level. If you cannot see the PDAS and ABS lights they have been disconnected. This is the most common. You do not have airbags so that can be discounted immediately.
Ciao,
Adrian
964C4

PS: Please be far more accurate and specific when asking for help.

Wachuko

If the car was working without problems before and this is just happening now... while driving all warning lights come one and you hear a buzzer... ..could be the Xmas light effect.

It could be one or a combination of the following:

1. Weak battery (First time it happened in mine I simply replaced the worn out old one with a new battery, all went away). This is where I would start... fully charge your battery and see if it goes away.

2. Ignition cables (spark plug cables) - simple test of checking late at night with no lights around the engine bay and start the car (ventilated area of course), turn on the car lights (hig beam) to increase load. Open the engine hood and validate if you hear ticking and if you see sparks jumping from the cables. If you want to make it more evident spray a mist of water over the distributors and cables and seat back to watch the show... replace all cables if you see sparks.

3. Distributor caps and rotors - you might have a cracked distributor cap These should be replace every 15k

See my other post.. I am just going through this. Having done 1 for the second time in three years it is time now to do 2 and 3

Good luck and keep us posted on the progress.

Wachuko

I did not see that...

if that is the case then your car might have a genuine fault. Follow the directions and answer the questions posted by Adrian...

clashmin

thanks for all the info- i checked and sure enough the abs and pdas lights were removed- jeez. I have not purchased new ones yet so I am not sure of the problem. But I have a new problem- I have a "porsche" friend that drove the car and said it sounded like it had a loose cylinder. I am not driving it now and am going to lift the car to see what I can. I guess first step is to remove valve covers and see if the cylinder is indeed loose- my question is: if it is loose, what are the possible resolutions? I know that I can drop the motor and replace cylinders and pistons, which i may do, but what are alternatives to this? By the way, the car is VERY dry underneath and doesn't burn oil that is visible.

Adrian

You do not have a loose cylinder believe me. Have a proper valve adjustment carried out.
When you install the light bulbs you will find you have a problem with the PDAS/ABS system. Seeing as you have just purchased the C4 I would be calling the PO and asking them why did they remove the bulbs? I know why but you should have some recourse against them.
Ciao,
Adrian
964C4

clashmin

thank you very much Adrian- the lights were taken out and i purchased the car from a private party "as is" so i probably don't have any recourse. On the other hand, the car was fairly inexpensive so i guess you get what you pay for. If the PDAS ABS lights are coming on once in a while (they do not stay on or necessarily come back on after you clear the warning- maybe for another 15 minutes or so) what are the typical reasons for this? I also posted another post a few days ago saying that i have a friction smell (clutch i thought) but now I am wondering if it could be the PDAS locking differentials at inopportune times. What do you think? thanks again.

viperbob

It does sound like a battery issue, or possibly your alternator. When the voltage in the cars drops to a certain level, it sort of resets some of the electronics as you describe. While driving, it may feel like the car did not miss a beat as the voltage to the spark plugs is less affected. Other things to look for with this include the radio just turning off and turning on real quick.

good luck...

Adrian

Once you have replaced the bulbs youwill need to report back on exactly what happens. You will need to note the conditions at the time, which light comes on first etc. This is quite a complicated system to troubleshoot especially if you do not know how it works. Even then it can run you around in circles. Removed bulbs normally indicates some troubleshooting was done and an expensive component was found or suspected and the C4 sold off.
Ciao,
Adrian
964C4

kedwards

Clashmin,

Maybe you should sell that popcorn machine, and buy a real 911...72 S


Kris

clashmin

I have done a couple of things this week- trying to diagnose two problems (warning lights and engine noise). First the engine noise- "porsche" friend directs me to a loose cylinder head, cylinder torque was checked and not loose. When running the car on a lift you can feel air coming out of EITHER the header gasket (right at the cylinder) or the possibly the cylinder to head seam. It is hard to tell because so much moves around there. I am going for new header gaskets to see if this solves the problem. Problem 2 is the warning lights. I (at the recommendation of Adrian) replaced all bulbs in the pod. When i turn the key on all lights come on including red AND green PDAS lights (in the book i only saw one listed). After driving for about 10 minutes the warning light, red PDAS light and buzzer come on at the same time. When I hit the warning light acknowledgement button the warning light and buzzer goe out but the red PDAS light remains on until I shut off the motor.