High,
I,ve heard there is a procedure to read out faults in Carrera2's with check engine lights; by turning the key to the second position and holding the gas pedal for three seconds and the releasing it, and then the check engine light will flash a number of times to tell if there is faults or not,I heard 5 consecutive flashes followed by 1 means no faults, I tryed it on my '91 and nothing happened, does that mean theres faults that need to be read out?, or am I doing it wrong?, or is there no such procedure? Anyone ever heard 'bout this?
964's rule****Geo****

 

Yes, that's a real procedure and it should work.

Here's what to do:

1. Put the key in and turn it to the ON position...where all the dash lights light up..
2. Push the gas pedal all the way to the floor.
3. When the "Check Engine" light starts flashing release the accelerator pedal...don't rely on a 3-5 second interval.
4. Once released it should put out the codes you're looking for.

I did this once on my car and it worked fine, but I have heard of others trying the same thing and having the test fail. My car's getting new tires so when I pick it up tomorrow I'll try it again and try to record exactly what it did for you.

Later,

Bill Wagner

 

Dear Geo,
The check engine fault code only reads out emissions failures. In fact there is only one code it gives out according to Porsche.
Now when you say you have a 1991 C2 which 1991 C2 do you actually have. Do you have a 1991 version of the 1990 version, built pre 01 Nov 90 or the 1991 version built after October 31st 1990.
The check engine light system was a 1991 California only requirement. Again as per Porsche documentation and manuals. The Nov 1990 and onwards USA versions only have this check engine light. The May 1990 through October 1990, 1991 versions of the 1990 model may well not have this system installed. In fact I am quite sure many of them do not. It may be wired up but it is not working. This will be explained in detail in my book. You also need a -03 DME to make this work properly and these were officially introduced in the Nov 1990 version of the 1991 model first in the USA then elsewhere. There are a whole bunch of different DMEs out in service as well.
Confused, yep I am sure you are, so am I but this was a period of mass confusion at Porsche as well,
Ciao,
Adrian
911C4
944

 

Thank You for the information gentlemen,
Adrian,the production door stamp has a date of Nov.12,1990,a "M" year code, vehicle #0960 and a black plastic intake manifold,is it a 1991 model?Its close but it should be,right? Your right man I am confused......
Thanx Bill, could you let me know how long you held in the gas pedal before you got a response, and if the code I described is accurate, I tryed again and held it for about 20 seconds but nothin happened allthough i did hear a light clicking sound while holding the pedal......
Thanx again......Geo

 

My car has a ... born on date of September 27, 1990. Somewhat odd to now have to think of my 91 C2 as a 90 model car. Anyway, the check procedure definitely worked and showed a 5-1 code. Turned key to on, held pedal until check light flashed. Released pedal and flashes began.

 

Don't forget the production year tends to start in August, not January. My 1981 911 was produced in September 1980. The production year was delayed due to labor problems one year, but otherwise it's pretty much the same.

 

GeoC2Cab:

I tried it again and it worked exactly as I described. I didn't measure the time I held the pedal down, but I guess it would be about 5-10 seconds. It actually lets a flash out when it's time to procede. The check engine light may be limited to the U.S. so if you're in another country, it may not function. On the other hand, maybe your check engine light is burnt out.

From how you describe your car, it should be a '91, and I would think that if it's a U.S. model the check engine light would work.

It's apparently possible to get the EPROM in the DME re-burned at a Porsche shop for a small fee (sometimes free), but you'll have to take the DME in to them to let them do it (or let them take it out $$$). I haven't been able to verify the accuracy of this procedure but it would make sense and it wouldn't surprise me. Maybe Porsche was only required to implement the check engine light for cars actually produced in 1991 (mine was finished in January of 1991 so we're only a few months apart).

Hope this helps,

Bill Wagner

 

Guys, the check engine light was only installed originally for the Californian 964s. It was later hooked up for all US versions only. This system was never activated elsewhere. The first ROW 911 with this system was the 993.
The Californian legislation requirement started in calendar year 1991. Whether Porsche pre-empted this and started installing the engine check light earlier (which I remind everyone does not check the DME faul codes, it only check one, the O2 sensor) I do notknow and I doubt that Porsche could tell you either.
Now to production data. Porsche rarely followed the August 1st to July 31st standard production year. My 911C4 was built in August 1989 (25th Aug is the date stamp) and is still a 1989 K series. The 1990 model year started production in September or October 1989 for the ROW L series.
If you have a 1991 model built between May 1990 and end of October you have a 1991 model but it is actually a 1991 version of the 1990 model and yes as the production line went on some of these got plastic intakes. Others did not. It is my understanding that the changes were gradually made on the USA versions first and in some cases only. If you have a Nov 1991 or onwards built version then you have what I call a real 1991 model or you could I suppose call them a complete 1991 model.
I have not been able to find one year ofg 964 production where Porsche followed the standard production year.
The production lines also did not match parallel either.
Again this is very important to know because people canbe chasing things that they think are faults but are not. Purchasing parts that do not fit ever or require some modifications.
Ciao,
Adrian
911C4

A pre Nov 1990 C2/C4 has a different rear suspension to the pst Nov 1990 models and other changes are airconditioning. These need to be watched out for. There are many others but I cannot post them all. Wait for my book.

 

More to middle of the road then... as mine is 9/27/90 - or a 1991 version of the 1990 model. Yet it does have the black plastic intake pipes.

 

OK, since I waddled into this, here is how Porsche classifies 964's model years. Look up your VIN. For US VIN's, it will start WPOxxx, where, the xxx are, for example, "BB0" or "CB2", rather than the ROW "ZZZ". The character in the middle of the next set tells what the model year is:

89 = 96KS4
90 = 96LS4
91 = 96MS4
92 = 96NS4 (non-RSA)
92 = 96PS4 (RSA)
93 = 96PS4
94 = 96RS4 (and 93 Carrera Speedster)

One book says there was a specification change in mid-1993 that caused the post May 1993 production to be listed as "R" (1994) series.

 

I have a 90 C-4. Don't really know why it works- I believe it is a CA spec car, and I sent the DME to Porsche for an upgrade- "free", at some point later, I popped in a bulb into the blank space, and it has worked fine. I have a list of about 20 faults which it supposedly reads. I tested it by connecting a known bad O2 sensor, drove it a while, and sure enought it read the flashes for bad O2. I see that Adrian stated that this is the ONLY code it will flash. I did not know that. Just for fun will try to screw up something else and run the experiment again. BTW- I just tried to activate the light on Jeff's 91 C2, and it did not flash. Another friend with a 92 C2 does work just as mine. Confusing isn't it? Worth just taking a bulb probably .50, popping it in-should take mabey 2 min, and see what happens.

 

A DME on a 964 (when equipped with the "Check Engine" feature) should be capable of reading at least the following malfuntions:

-ECM power supply lower than optimal
-TPS
-Engine Temp sensor
-MAF
-Idle control circuit
-Intake air temp sensor
-Open circuits on fuel injectors

It appears that as the cars get newer, the more they can do, so the list above is MINIMAL.

Later,

Bill Wagner

 

Dear Bill,
I am afraid the Porsche Manuals do not agree with this list at all. Are you sure you are not talking about the OBCI equipped 964s. USA only with the computer mounted in the Tacho,
Ciao,
Adrian
911C4

 

Adrian:

From AllData, here is a quote:

Trouble codes may be read using code tester tool No. 9268 or system tester tool No. 9288 or equivalents, or through flashing of the ``Check Engine'' lamp. To display the stored trouble codes through the ``Check Engine'' lamp, proceed as follows:

1.With engine off, turn ignition switch to ON position.
2.Depress accelerator pedal completely for 3-5 seconds.


I noticed that in another section they gave an example of using the check engine light and they referenced an O2 sensor as an example. The codes I referred to were from a Haynes manual, but looking at AllData's site, I now get the impression that perhaps the check engine light can provide even more information. This would be normal for a car made for the U.S. market.

I also checked this with the U.S. version of the service manual. The check engine light is described on page 24/28-33, and it lists the codes as being those in the table identified on pages 24/28-7 and 24/28-8. For my particular year (1991) there are more codes listed than those listed above (for example, a knock sensor failure can also be detected).

All information I refer to will reference U.S. cars. Please keep that in mind for future reference. I have no idea what is or has been sold world wide, and it's an issue I'm not going to pursue.

It is entirely possible these are U.S. models only...in fact I suspect it.

Have a good day,


Bill Wagner

 

Dear Bill,
My Porsche manual happens to be the US version of the manual and the OBC combined with the -03 DME were fitted as "standard option" and standard respectively in 1991 US Versions built after Nov 1990. Many 1991 version of the 1990 model may or may not have been fitted with these items. For any 964 headed for Califonia this is possible.
The 964s without OBC can only read out the oxygen sensor fail code IAW the Porsche 964 Carrera Maintenance Manual. Fault codes I believe we expanded with the US Only OBCI mounted in the Tacho installation. However I have no definitive proof of these fault codes. If you have a 1989 or 1990 964 of any kind in any version then none of this stuff will work unless a retrofit and DME upgrades were carried out. Early 1991 US versions will not have this. From around July 1990 onwards some US versions may have the OBCI. Check your tachos,
Ciao,
Adrian
911C4

PS: Much of the technical data descriptions on alldata are not correct. They are in conflict with the manual. The manual is always the correct data unless proven otherwise.
Another one is the AWD is electronically controlled.