Hello All

i am new to Rennlist. i was referred to this group as potentially someone can help me.

i have 1991 porsche 928 S4, i need to access the computer but cannot find the correct diagnostic tool necessary to read the computer in my car. can anybody help please thank you

rgds

 

Lets start with whats wrong..

 

The 928 is pre OBD. So modern scan tools do not work. A Bosch Hammer can help but they are hard to find. JDS also made a tool but it really only worked well on 89’s.

if your car is no longer running and if you suspect it is the computer you can send it out to be rebuilt.

As Speedtoys asked we need more info on what is wrong.

 

The Bosch Hammer is indeed hard to find and expensive. BUT, the 928 Owners Club (www.928OC.org) owns one and loans it to members free of charge (credit card deposit required, refunded when Hammer is returned). Shipping both ways paid by the 'member'. Contact the membership Chairman or the Treasurer for more information. Another alternative is a computer program developed by Theo Jenniskens (Netherlands) that is available to buy and download onto your laptop (contact is: theo@jenniskens.livedsl.nl:

Gary

 

Hello there, car is actually running quite good. the issue i have is a bunch of lights flashing on the dash and messages showing up. these are the following messages and or lights.
the word Differential shows up on the led screen, Tre pressure shows up. brake pads shows up. also cat shows up. the lights that show up are the stop lamp. a picture of the 4 tires connected like a H. a light that says CAT TEMP. the car works find but all these lights and words are flashing all the time. as i live on an island in the caribbean i am limited . my mechanic downloaded an older version software for his tablet to communicate with the car but it does not . we even bought an adapter wire as the porsche has a round 9 pin plug and his tool has a square plug. so far no luck

 

Hmm that likely has nothing to do with the computer. I would start with the simple stuff like cleaning all your grounds, inspecting the gauge cluster and circuit board film.

 

Sounds like you have a 90-95 Japanese market car with a bunch of needs. There's no modern tablet that's going to work with any adapter, you need a dedicated tool like a Bosch Hammer, a Durametric (http://www.durametric.com/porsche-928.aspx) or a UDT-999 tool from Theo Jenniskens. https://928-ecu-repair.com/diagnosetools_udt999.html

 

But what will those do other than READ problems, that he can already see.

 

Fair enough- short answer is 'nothing' for the brakes, RDK and the cat temp warning. For the Diff message Theo's tool (and I assume the Hammer, though I have not used one) will at least display error codes that will narrow down the source of the error message (ABS sensor, the PSD lock valve, etc).

DiegoT, it would be helpful to post details about your car (year, US vs. rest of world market, transmission) and maybe pics or video of the dash messages. The trivial explanation for the brake and tire warnings are that you have worn brake pads or a worn brake pad wear sensor, and low tire pressure (The tire pressure sensors trip at a relatively high pressure). The Diff warning could be any number of issues in the ABS/PSD system. And the Cat temp warning I think was only used on the Japanese market cars (but maybe other ROW markets, dunno), but if the car's running ok (on all 8 cylinders) then I'm not sure why the CAT warning is lit.

 

... or the individual systems being identified by the cluster. Are you 100% sure that all of the things that pop up on the dash are in fact working properly? A single bad electrical connection that makes intermittent contact for any light bulb will throw the bulb message. Same thing with the brake pad sensors - a bad / intermittent connection will throw the brake pad warning. Ditto for the TPMS system, O2 sensors, etc.

+1 on cleaning up all electrical connections and grounds. You are in the Carribean so the moist salty air certainly doesn't do them any favours. Clean al the grounds, clean all connectors with some contact cleaner or Deoxit spray and see what happens. If you only clean up the brake pad sensor connectors, does that particular warning stop showing up?

 

Diego,
- The CAT temp warning will most likely come from a wiring issue - probable cause a broken wire down by the exhaust.
- The tire pressure warning will come from a fault in the system somewhere. Many have tried to fix the system, few have succeeded. Most unplug the connector from the RDK (TPM) brain and put in a jumper wire to disable the warning. https://rennlist.com/forums/928-foru...ng-bypass.html
- The differential warning relates to the rear diff electronic lock system. This could be a multitude of things and is probably the most difficult to track down.
- The brake warning is most likely a worn sensor on one of the brake pads. This would be an easy fix as the system triggers when a circuit to ground is found. A new sensor or some electrical tape will most likely be the cure.

Myles

 

Send me a PM.

 

This sounds as if you have multiple ground faults or inter-mitten electrical shorts... especially if the car is running & driving with no obvious issues. If you haven't removed and cleaned ALL the grounds throughout the car then finding, cleaning, spraying with DeOxit, and retightening those would be STEP ONE. There are a few places on this forum with diagrams of the ground point locations, although they can be model year specific.

Start with the "sticky" threads & FAQs at the top of the forum. You'll find a lot of information.

 

Good Day, i do not think it is a japanese version as the automobile is a left hand drive car. will this tool be able to reset my blinking lights on my dash, cat temp, differential, tire pressure, tire pressure, brake pads, light flashing showing the 4 tires connected by a H or drive train icon. the car drives perfect but we have all these flashing and blinking lights on my dash.

 

Hello Myles, thank you for your reply i have forwarded your reply to my mechanic and he will look into everything you mention, would it be possble for me to send you some photos of the flashing lights on my dash as i do not know what some of them are for. i live on an island in the caribbean i own the only 928 on the island my mechanic is pretty competent but is also limited in knowledge and hardware/diagnostic tools