cajonfan

Hi 2000m2,

That's probably not an appropriate question for me to answer. I absolutely understand that some of us would rather borrow or share their tools and experiences. I also understand that some would rather not loan out their tools. My goal is just to make the ABS test tools available. There are way more cars that need access to these tools than my ability to produce them.

So let me ask the question a different way for you - Are there any C4 guys in the Bay Area interested in helping out 2000m2?

Michael

2000m2

Thanks Michael. I would prefer having someone around who knows how to use this type of tool. I also just moved and likely won't have access to any of my tools for the next month, at the earliest.

biggynuts01

My ABS and PDAS light would come on after 10-15min of driving. I replaced the bomb, pump switch, and bled the brakes... Still there.

It was fixed when I replaced both accelerometers. They detect aceleration and side to side movement, and if they are faulty the ECU cannot compute correctly and shuts down ABS and PDAS.

2000m2

Thanks for the input. I just dropped my C4 off at a shop this morning. Will see what they come back with and I'll keep this in mind to mention it when I talk to them.

me964

PDAS will not be shut down (all-wheel drive function will always be operational !)

if ABS is shut down, the ABS warning light comes on and at the same time triggers the PDAS warning light - of course, the complete brake system will still work (minus ABS)

C4inLA

Car should never be rolled on to rear wheels only Dyno! Smog check shops must have 4 wheel dyno or no dyno testing during smog checks! As he said, AWD all the time......

FeralComprehension

While this is perhaps pedantic, PDAS <> AWD. PDAS is the system controlling the active difflocks in the center and rear, so while you're correct that AWD is always active in the event of an ABS/PDAS system fault you can expect the active traction/anti-yaw control to be inoperable.

ETA: http://www.adrianstreather.com/docs/...overviewR2.pdf

-nick

Don't expect warning lights to tell you that the pdas or abs has a fault either. There are some invisible failure modes for each system. The tech is far from perfect.

me964

yes

have that problem with my car at present


yes

even one faulty ABS-sensor will trigger both warning lights


first thing I will do in the spring, is check the whole system with Michael`s C4-tester

https://rennlist.com/forums/964-foru...or-orders.html

kta

Finally, going to pick up the car @ the end of the month.
Unfortunately, no luck fixing the warning light. The mechanic still thinks it's the ECU brain - so the only options from his perspective is to find a swap unit to test > validate purchase OR get it from the dealer (which should be warrantied).

I appreciate all the advice though, so I'm going to check all the grounds and power first and the connector/pins once I get this puppy home.

On a side note, I've been looking into documentation on the car. Though I plan to find a good mechanic in my area (SF Bay) I want to DIY as many repairs as possible, and ran into this book: https://www.amazon.com/Porsche-911-9...ds=porsche+964
Does anyone own or have used this and found it helpful OR have another source the recommend?


Thanks,
Kevin

911S3.6

Kevin it sounds like you have done a lot of checking but i did not catch whether or not you tried
just unclamping the big pin connector to the ABS Computer [ in blue ] and spraying contacts with contact cleaner. Then clamp and unclamp a few times so the friction cleans off the pins.
Then spray and clamp it back down.

My 91 C4 sends up the christmas lights PDAS/ ABS every once in a while- mainly in warm or humid weather; not at all in Winter. Anyway, this is definitely the problem with mine and is not a big deal and easy to service.
hope this helps - these are wonderful cars.

me964

well, it`s (one of) the bibles

overhere in europe the price is twice as high ... so you can`t go wrong !

kta

Thanks 911S3.6 & me964!

I have not checked the connectors yet... but I will certainly give that a try.
Also - will order that book.

kta

@911S3.6 - do you have a recommendation on the type of contact cleaner i should use? Is it something that i can just find an home improvement or dept store?

Finally brought the care back to it's new home! It drove great all the way - this weekend is my project to check the contacts of the big pin connector + see if all the grounds/power is working OK. Any other recommendations on what to take a look at if those both are unsuccessful?

Before I took the car home, I opened up the connector - and it looks clean - no signs of erosion, water damage, or wear (at first glance).



Thanks,
Kevin

Porsche930

Hi Kevin, I believe any professional strength contact cleaner/spray should work. I particularly like CAIG DeoxIT D5 brand in my high-end audio metal to metal contacts cleaning and maintenance and it can be used in our Porsche connectors.

By the way, where are you in the Bay Area? Do you go to EASY on 1st Sat or are you planning to the upcoming meet up/swap meet in SJ on 3/26? I do tinker with my C2 Targa every now and then, so it would be fun to meet up some day with our 964s.

Tony
SF, CA