??? About Codes 51 and 32
 

Howdy all,
Finally broke down and went to Goodyear to get the codes. It threw a 51 (EEPROM Programming Error). If I'm understanding this one right, my PCM is probably toast. The other was 32 (Exhaust Gas Recirulation). If I'm understand standing this right, it could be a vacuum leak from who knows where, a bad egr, a blocked passage, or an exhaust leak from who knows where.
The EGR gets info from a lot of sensors, is it possible one of them could be bad, or shouldn't they throw their own code?
The SES light is intermittent, I've had it at high acceleration and at idle, nothing consistent, and it doesn't stay on all the time. Many times I drive it, the light doesn't come on at all.
If the PCM is toast, could it cause the DTC 32 since it has/is loosing it's programming? If the PCM was toast, wouldn't the SES light be on all the time? Can you just change the EEPROM chip, I'm sure I've seen aftermarket ones with mucho horsepower. Would the PCM have to be reprogrammed if it's replaced. The Service Manual says it's not replaceable but I"m sure that's wrong.
Where would you all start?
I was getting ready to order the Scanmaster, but this is probably gonna put that on the back burner. Or do you think that could help isolate the problem?
Thanks for any help or suggestions,
Gabe

Don't panic. The complete failure of a PCM is very rare.

DTC 32 is the diagnostic for the EGR. It simply means when the PCM told the EGR valve to open, the PCM did not see a blip in the MAP sensor reading that it expected. This code is also fairly rare on the OBD-I (93-95) models. But it can happen, and it will be intermittent. The light is only on when the code is "active". And the code can be active only when the EGR valve is supposed to be operating, which is not all the time. Once the light goes off, the code remains as a "stored" code.

The EGR does NOT "get info from a lot of sensors". It is an acutator, that recieves a pulse width modulated vacuum signal, by way of the PCM pulsing the EGR vacuum solenoid.

Your 94 does not have a removable chip. 93 was the last year. As indicated in the manual, you replace the entire PCM, not the chip. You wouild only reprogram the PCM to reflect your VIN and trans type.

I would clear the codes (pull the "PCM BAT" fuse in the panel at the end of the dash for 30 seconds) and see if the codes come back.

Goodyear wiped it already. Where do you recommend I start if they do come back?
This is starting to sound like I should've already installed a Scanmaster.

Hey,
The code 51 has stayed away, but the 32 is back and seems to be more frequent especially when coasting down from accelerating. Can a vacuum leaking gas cap cause this? Where should I start? Anybody know what readings the Scanmaster should have for EGR at different rpm ranges? I'm thinking if I go to the trouble of taking the EGR valve off to clean the ports, I just as well replace it and the solenoid while I'm at it.
Suggestions?
Thanks,
Gabe

You can manually move the EGR diaphram at idle and the car should stumble hard or even die . Mine was completely frozen at 150,000+ miles, couldn't move the diapghram at all. No codes ever though.

It is easy to remove and inspect as long as you have a stubby 1/2" combination wrench. I don't know of the solenoids being bad that often.

Let us know what you find.

Sean

No, a leak in the gas cap will not set any codes in OBD-I. It will not contribute to an EGR code.

Using a scanner, all you will see is the % opening the PCM is commanding from the EGR valve. It will not actually tell you if the EGR is working.

It isn't a solenoid electrical problem, because that would be setting code DTC 27.

I would focus on cleaning the valve and the port in the back of the intake manifold. Also check the vacuum lines to make sure they aren't cracked.

I didn't notice there was a code for the solenoid. That's cool. Eliminate that.
Thanks for the suggestions.
Gabe