Faulty PCM?

bavariancaddy · #1 (**permalink**) 01-12-06, 08:48 AM

Hi guys, some of you might remember that I had a current P023 trouble code on my 95 eldorado. Well after replacing the spark plugs, wires, the complete ICMand the EGR valve, the trouble codes appears again. On the display I can read by the PCM Data, PD07 34 til 179 when I drive, 35 at idle, 35 engine off and 35 at WOT,it seemed to me at the new EGR valve is working, therefore my question to you: Could it be at least the PCM which isnt working correct, what do you think. Thanks Franz

Eldyfig · #2 (**permalink**) 01-12-06, 12:02 PM

The PCM is one of the possibilities. In order to properly test it, you will need a multimeter to check some resistances at the pcm connections. Do you feel up to that?

Those data numbers for the egr valve are correct. If code P023 was current, your egr valve should have been disabled though.

The only reason EGR is on the end of that description for P023 is that it would be stating "EGR disabled." The egr is not the cause of this code.

bavariancaddy · #3 (**permalink**) 01-12-06, 01:51 PM

[quote=Eldyfig]The PCM is one of the possibilities. In order to properly test it, you will need a multimeter to check some resistances at the pcm connections. Do you feel up to that?

Those data numbers for the egr valve are correct. If code P023 was current, your egr valve should have been disabled though.

The only reason EGR is on the end of that description for P023 is that it would be stating "EGR disabled." The egr is not the cause of this code.[quote]Hi Eldyfig, I will try to check the resistances at the pcm connections at the weekend , I remember there was a diagram shown the wiring and the the resistances at another thread about the p023 trouble code. Thanks Franz

bavariancaddy · #4 (**permalink**) 01-13-06, 04:59 AM

Quote:

Originally Posted by Eldyfig

The PCM is one of the possibilities. In order to properly test it, you will need a multimeter to check some resistances at the pcm connections. Do you feel up to that?

Those data numbers for the egr valve are correct. If code P023 was current, your egr valve should have been disabled though.

The only reason EGR is on the end of that description for P023 is that it would be stating "EGR disabled." The egr is not the cause of this code.

Hi Eldyfig, what do you think, could it be that the crankshaftsensor is the cause of the trouble code, is there only one at the engine or are there two. Maybe if the pcm gets wrong datas from the sensor, the ignition timing is not correct. Can I read the pcm datas for crankshaft sensor at the pcm input and what are the correct datas? Thanks for reply. Franz

Eldyfig · #5 (**permalink**) 01-13-06, 07:09 AM

There are two crankshaft sensors. There is a code specific to them that would set if they were the problem. That would be:

P083 ... Crankshaft to Ignition Module Failure

You also have a camshaft sensor. There is also a code for it.
If you were looking for that flowchart from the earlier thread, it is here:
http://www.cadillacforums.com/forums...ad.php?t=59062 (P023 code on 95 Eldorado)

bavariancaddy · #6 (**permalink**) 01-13-06, 07:21 AM

Quote:

Originally Posted by Eldyfig

There are two crankshaft sensors. There is a code specific to them that would set if they were the problem. That would be:

P083 ... Crankshaft to Ignition Module Failure

You also have a camshaft sensor. There is also a code for it.
If you were looking for that flowchart from the earlier thread, it is here:
http://www.cadillacforums.com/forums...ad.php?t=59062 (P023 code on 95 Eldorado)

Thanks for your help, I`m gonna check the wiring and the resistances like shown on the flowchart `til monday next week. I will tell you the result on tuesday. Franz

bavariancaddy · #7 (**permalink**) 01-17-06, 06:51 AM

Quote:

Originally Posted by Eldyfig

There are two crankshaft sensors. There is a code specific to them that would set if they were the problem. That would be:

P083 ... Crankshaft to Ignition Module Failure

You also have a camshaft sensor. There is also a code for it.
If you were looking for that flowchart from the earlier thread, it is here:
http://www.cadillacforums.com/forums...ad.php?t=59062 (P023 code on 95 Eldorado)

Hi Eldyfig, well I checked the wiring and the resistances like shown on the flowchart, nothing unusual, my opinion is it only could be the PCM. I`d just looked at car-parts.com for a remanufactured pcm. There are more pcm for the seville or deville, is it possible to replace my eldo pcm with a seville or deville pcm? In other threads I red that I have to take the old prom into the new pcm? Is there anything else I should know. Greetings Franz

Eldyfig · #8 (**permalink**) 01-17-06, 04:25 PM

I don't no the answer to that one. If no one else posts an answer, you might want to start a new thread titled appropiately for changing out the pcm. I am sure someone should be able to help. Unfortunately, I haven't tried to switch pcms between different models.

delzy · #9 (**permalink**) 01-17-06, 10:23 PM

I was the victim of a failed PCM on a 95 Seville SLS a short while after we got the car.I found a brand new PCM (came without EEPROM) on eBay for about $75 shipped. I moved the old EEPROM to the new PCM and installed it and the car was fixed. You may find greater detail here:

http://cadillacforums.com/forums/showthread.php?t=45720

Anyway, make sure to write retrieve the transmission fluid life before you pull the old PCM. Then once the new one is installed, update the value through the DIC. The switch was easy and I also bought another spare. You just need to look at the AC Delco part number. The PCM works on all N* modelsfor 94 and 95 I think.