learning more about my 993 and !

[Leo O'Farrell]

My polar silver 993 Carrera is a very early car, made in March 1994. The mechanic who bill me $200 to try and fix my codes said the electronics are a mix of 964 and 993 components.

For example, the port to read the codes is in the passenger footwell and takes a round OBD1 connector.

He tried the Bosch Hammer, Porsche's reader and Durametric (sic) reader and couldn't access the Anti Lock ABD control unit. Says this is a $2,000 part.

So, I'm driving around with a red ABD light Yellow Anti Lock light, red spoiler light, and a non-functioning Speed Meter and digital computer.

Any suggestions - go to the dealer as perhaps they have more experience or more equipment to better diagnosis, buy a second hand ABD and Antilock control unit and get it installed?

Thanks.

Leo

[frf]

The non functioning Speedometer implies the red spoiler light on and a non functioning computer, because they are both working with signals provided by the Speedometer. Now, the ABD red light on means a problem in the ABS system. since ABD works using signal provided by the ABS. The same happens with the Speedometer which receives a signal provided by an ABS sensor (in Europe the one provided by the sensor connected to the rear left wheel). So, and this is my guess, you might be facing a problem with the ABS system. Is the ABS warning lamp on? Does it light up when you turn on the car during the system checking? Are all the 4 ABS sensors OK?
Francisco

[rsr91128]

I have a mar 94 US 993 also. I purchased a used durametric with the old OBD I cable from a 964 owner. When I first used it I thought it was useless, then I downloaded newer software from their site and it got better but...

I couldn't get it to communicate with the Airbag module. As a last chance I backed out of the 993 menu and selected a 964 instead and it worked. I reset the light (had the 2 minute delayed light from previous low voltage) and has never returned. It is strange because when it is connected it shows as a B04 module which is right for a early 993, but the 964 page says it should be a B02, oh well it worked. I can't remember if the ABS linked under 993 or 964? There were no codes so I really can't recall.

You might have him try to log in as a 964 and see if it will communicate with the ABS, my car doesn't have ABD so I don't know if that has anything to do with it either.

FWIW I really like the newer durametric software with realtime numbers and datalogging capability. I would buy new if I had to.

Good Luck with your 718 code, they are great cars.


BTW, there is a pretty good description and troubleshooting of ABD in the back of Esential Companion that may help.

[Leo O'Farrell]

Originally Posted by frf

The non functioning Speedometer implies the red spoiler light on and a non functioning computer, because they are both working with signals provided by the Speedometer. Now, the ABD red light on means a problem in the ABS system. since ABD works using signal provided by the ABS. The same happens with the Speedometer which receives a signal provided by an ABS sensor (in Europe the one provided by the sensor connected to the rear left wheel). So, and this is my guess, you might be facing a problem with the ABS system. Is the ABS warning lamp on? Does it light up when you turn on the car during the system checking? Are all the 4 ABS sensors OK?
Francisco

Yes, there is an orange or amber ANTI-LOCK light glowing as well. All the lights seem to light up when preparing to start. I'll ask him if he checked all four ABS sensors.

Thanks.

[Leo O'Farrell]

Regarding:

You might have him try to log in as a 964 and see if it will communicate with the ABS, my car doesn't have ABD so I don't know if that has anything to do with it either.

BTW, there is a pretty good description and troubleshooting of ABD in the back of Esential Companion that may help.[/QUOTE]

Yes, I'll ask, the shop is a ten minute walk from my job so I might swing by and ask.

Need to get the book and probably the software as well.

Thanks.

[frf]

Leo,

Just to verify if the ABS control unit is working fine, disconnect one of the ABS sensors in the wheels and see what is the reaction of the ABS control unit. If it is ok, the ABS light must go on warning about problems in the ABS system.

This was one of the things I did to check the ABS control unit in my car when the Speedometer stopped working and I was doing a trace to locate the source of the problem.

Francisco

[Leo O'Farrell]

Well, my car doesn't seem to have an ABS light, just Green and Red ABD lights and the amber or orange ANTI LOCK light. My red ABD light is always on as is the ANTI-Lock light.

I checked with durametric and here's what they said:


Thank you for contacting Durametric. The ABS control units on the 993s
were notoriously prone to failure. This led Porsche to install either
the 964, or 996 ABS control units in lieu of the 993. We recommend
trying either of these. If the unit still fails to communicate, it is
quite possible that it is simply faulty. I hope this has answered your
questions. Please feel free to contact us with any others.

Best Regards,

Will Howe
Durametric

I did find some secondhand units on EBay and am considering trying to swap it out....

[Leo O'Farrell]

Car sat for two weeks, battery hooked up. Ordered 993 Essential Companion based on a advice here and it does have an excellent troubleshooting section. Before the book came I checked relays, fuses and control unit connections. Everything seemed OK.

Started the car today, no trouble lights, the speedo works, etc. Took a 1/2 hour drive including starts, stops, high revs and no trouble lights. Don't know what to think.

I'm going to do the battery tests as described in the Essential Companion book as an old post on this subject suggested a bad battery or an alternator as a possible problem.

The battery is a few months old, so I want to check the alternator. Quite an bunch of surprises, these cars.

Did enjoy the Sunday drive today.

[Deadeye]

I periodically get ABS trouble light in my '96 993 at start up. I just shut it down and re-start the engine. This clears the lights. Works like a re-boot of the desktop computer.