Travis.

Hi Gang,

I sent a message to Viken and Robin already, but thought all of you might also know the answer to my question.

The mystery light appears left of the ABS idiot and appears as a (0). Within the 0 are two arrows pointing at each other. The color is red. It is NOT documented in the manual.

All of the lights except for this one go out once the car is running. Also, the only way the car was going to wake up was if I jumped started it.

Also, the blower is not turning off after the key has been removed. You can still hear it humming along unless I pull the #1 fuse (25A) and then re-insert it. huh???

thanks in advance guys!

-travis
993 C4
Belmont, CA

tom_993

What year 993? The early '95's had a wiring harness issue (see archives) that could cause all kinds of mysterious electrical gremlins, including, I suppose, lighting up an unused idiot light.

Viken

Travis,

I just saw your e-mail. This light comes on when I first start my car and stays on for a few seconds before it goes out. It is the only one along with (!) that stays on longer than the rest. If I remember well, it has something to do with the AWD's braking system. Something about pressure build-up or the like. It is definitely in the manual as I have seen a blurb saying something like "if the light stays on, take the car to your dealer."

Viken

What happens if you don't take the fuse off? Does the blower just keep going? Usually and when it's hot, the blower cycles off and on for a few minutes before it stops for good.

Ray Calvo

Don't know if you are pulling our leg on having a manual or not. Does it cover other C4-specific items? Because this light is a low brake pressure alert, tied to your hydraulic brake pressure boost. And I am very surprised that Porsche wouldn't describe such in their officiallly-supplied owner's manual.

System sounds very much like hydraulic brake boost on old Audi Coupe Quattro. When started having problems with it, warning light stayed on for a period after startup. Then it stayed on longer and longer. If it was off, pumping the brake pedal with the engine running would cause it to light after maybe 10-15 pumps. Eventually stayed on permanently and I had NO brake boost! Turned out to be a pressure accumulator/check valve in the circuit.

You might have an air bubble in the pressure hydraulics circuit, or a problem with the hydraulic pump or associated components. Diagnostic requires the Porsche 9288 system tester, likely a pressure gauge, and a shop manual -none of which I bet you have.

Visit your dealer before you kill yourself or somebody else.

Travis.

Viken,

Thanks for the reply. I double checked the owner's manual and nada...

I'll take the car for a drive to see if the light eventually goes out. It has in the past, so perhaps this is just a fluke? (i hope)

As for the blower, yes the blower acts as if at the 0 setting. Key off, blower still on even if left sitting in garage. Pull fuse, blower off, fuse in, key in, blower on, key out, blower off (sometimes) I think it's related to low voltage myself.

cheers!

-travis

Fred 993C4S

Just happen to have my manual at hand for a 1996 C4S and it is on page 51, top left hand corner.
Carrera 4, 4S, Turbo: Brake pressure warning light. Check it out again and take it in for service.

Fred

Timothy Stewart

I have 95 993.

Its in my manual (WKD 993 021 95, 1/94)
but the manual is wrong.

The diagram of the large instrument cluster on p58 does not show the light.

The text talks about it, but the icon
of the light next to the text on p59
looks like parentheses, circle, exclamation
point.

The light itself is as shown in picture
above.

tim

Travis.

Okay. just went for a drive...

Ray, didn't come close to killing anyone.

My suspicion is that the low pressure in the accumulator was signaling the idiot light to turn on.

Car has not been driven in 10+ days. My bad.

Also, battery is definitely dead. Came home, turned off car, tried to restart...It's dead Jim.

After a jump(again), upon restart, all lights are off!

Anyone know where to get an Optima or should I just go to the stealer?

thanks again everyone!

-travis

Anir

Travis, I have an Optima Orange Top installed in my car. It is a newer, 835 CCA unit with "reverse terminals" released last year. "Reverse terminals" means that they are in the right orientation for our p-cars.

I bought the unit directly from David Willman at Optima (800) 292-4359 x 486 for $135, including shipping from Tennessee to Kentucky.

BUT, let me warn you about a couple of things before you decide to proceed. In my 1997 993TT, the positive battery cable as a decidedly rigid 90 degree kink at the end which did not allow it to reach the positive terminal on the Optima, which is located rather far inboard on the unit.

To get it to work, I used a battery disconnect switch available for about $10 from Tweeks. This did the trick, but the switch sits rather high and jams right up against the bottom of the trunk liner. It's a tight squeeze.

All in all, I'm still happy I went this route: better cold cranking amps, no risk of spilled battery acid & subsequent corrosion (and no need for the vent tube), and absolutely zero maintenance.

BTW, the same light comes on periodically for a few seconds in my car. It's definitely discussed in my 1997 manual. It may have to do with the Turbo big red system pressure accumulator (which is also found in the C4S, but I don't know if the C4?)??? As others have stated, it's not a problem as long as it goes off within a few seconds of starting to drive the car (mine always does).

Good luck!

Anir

Let's try that again.

Ran

I was told that it was the brake pump or something related to the brake getting ready for some action.

Since the ! (exclamation) indicator stays on as long as the double arrow indicator stays on, I wait the 15-20 seconds it takes to drive off. It is also the time it takes to tighten seatbelt, wear sunglasses, put away mobile, etc.
Both arrow indicator and exclamation indicator switch off at the same time and then it is VROOOM until 8 o clock oil temp (about 5 minutes driving) and then VROOOOOOOOOOOOMMMMMMMMMMM )

I think I remember reading that one should move after all those lights are off

Also, seeing as you did not drive for 10 days, perhaps the Porsche Battery Maintainer may interest you. It is Part number 000 043 202 56 My car started right up after a 11 day vacation which was followed immediately by a 10 day trip.

Also, what "blower" are you writing about Travis? Fan? Or the brake pump noise? There are a bunch of fans that need to go off as part of the cooling system... atleast that is how it is in my car after I shut it off.

Hope things work out okay. Best of luck.

Cheers

Larry T.

Travis,

If you have a 95 c4, you will not be able to find the information on this light in the owner's manual. There is a supplement to the owners manual dealing only with carrera 4 features, one of which is the brake pressure boost pump to which you are referring. If you do not have a copy of this, I can email you one.

I have a 95 c4 and have sent this to others on the board in the past.

Larry

Travis.

Ran,

The blower I am speaking of is the one for the interior. (HVAC)

Anir, thanks for the info on the Optima. I'll give it some thought tonight and decide what to do. The factory battery is the same price (~140) so price is a non-issue.

Happy to say everything is okay now. My pressure accumulator has been humming on and off as usual so hopefully, as soon as the battery is replaced all will be well (fingers crossed).

I read and reread the owner's manual and still could not find mention of said light.

Looks like I'm going to have to drive more and park less!

-travis

My Q Ship

Travis,

I think there is a updated HVAC control unit for the early 993s. Has anyone else heard of this? If not, your local dealer SHOULD be able to tell you if there has been a parts supercession.

Good luck,

Q