I have a 1991 F250 that has had a few issues, mainly rough idle and poor gas mileage. It's a 460. I have been getting codes from it and the latest was code 32 related to the EGR valve. I took it down to a shop and they told me that my EGR valve is stuck open and that the PCM is intermittently going bad. It took them about 2 hours to diagnose it. They didn't replace the EGR valve. They said the PCM is going out and that Ford does not make them. I said maybe I can get a replacement at a junkyard. They said they don't put used product on. Fine.

I took my old one out, it's serial # F2TF-12A650-JA.

What do I do now, go to the junkyard and hope for the best? Am I likely to just get another bad one? Why would it have gone out? In reality, if this thing is just a circuit board, they GENERALLY should be pretty reliable! Unless it got too much voltage to it and fried it.

 

I once had one that intermitently went out to lunch. It took quite awhile to diagnose. There's lots of components in there - it only takes one failing to cause a problem.

Ignore the part number - you want to look for one with the same catch code - it's usually 3 or 4 letters. You might be able to use one with a different catch code, but that can be a hit & miss proposition - donor needs to have the same engine and drivetrain.

 

It's the capacitors mounted to the circuit board that typically go bad. Before I would trust what the shop is telling you about the "PCM is intermittently going bad" what issues and other codes are you having? No sense going off on a wild goose chase only to find out they were wrong.

I found your other thread: Intermittent rough idle. Anyone have any suggestions?

If you do end up really needing a PCM, you will need the part number as well as note what the catch code is to verify you are getting the right replacement PCM.

 

Open it up and check for any leaking capacitors.

I've never heard of the term "catch code" to refer to a Calibration Code but I'm guessing it's the same thing.

I would ask the local Ford dealer.

 

There used to be remans available -- don't know if that's still true. Might try a little web searching.

I did buy a junkyard PCM once (mopar). This was a pretty big place and they had them in inventory. Asked how they knew if they were good -- said "we take them out of cars that still run. "

I have heard of Ford PCMs and bad electrolytic caps before. Some guys have fixed them by replacing the electrolytics.

But, do yourself a favor and check the EECIV relay and other power wiring too. If you have crappy power the PCM will act up.

Just my .02 -- good luck,

hj

 

All I can say is sometimes the truck will run rough, sometimes it won't. Sometimes it shifts hard, sometimes it doesn't. I got a code 67 so I got under the truck and adjusted the neutral safety switch. That worked for a while. And all this time, I've been trying to pin down the intermittent rough idle. So I got a code 32, something to do with an EGR valve sensor. So I called a mechanic and told him I got a code 32, something to do with an EGR sensor. He asked if I wanted the EGR valve replaced. I said no, I'd like everything tested to see what is wrong. I didn't say anything at all about intermittent.

So they had the truck for 2 hours. Ran it for a while, shut it off. Ran it again, shut it off, (it was mostly off though). Then after about 2 hours they said the EGR valve is stuck open but the PCM is going out. When I went out there they had something hooked up to the battery. They did not offer to replace the EGR and made it sound like replacing the PCM is priority, but it's obsolete. I can't believe this truck has a piece of obsolete computer equipment that threatens to make it inoperable!!!!!

Anyways I am new to this computer crap and wishing I bought an older truck at this point (or newer one), that didn't have computer stuff on it that can't be replaced. I have never heard of that. Wondering if that's why the owner sold it.

EECIV relay? Never heard of it? Not sure what else I can do. I think the PCM is unavailable and hit 5 salvage yards but none had a 460 E40D.

So, I can take a gamble on another used one for like $150 or spend like $250 for new old stock refurbished ones... not really sure how to go about proving/disproving it's bad.... and I'm thinking the mechanic wasn't trying to gyp me by not suggesting to replace the EGR after looking at it and saying they can't replace the part that needs to be replaced?

 

One thing I noticed is it seems my power is out of whack. For example the alternator gauge can sometimes sort of bounce around a little when at idle. And when I hit the power window button, the battery gauge jumps. And if I hit the button to roll the window up when it's already up, it's like the instrument cluster gets dimmer and the alternator gauge registers a lot less volts. Seem to me a window motor shouldn't do that much drainage.... is this what you mean by the power circuit? In that case how do I go about handling this? Battery is 6 years old but tests good at Auto Zone (truck came from Idaho, no way would that battery be alive here in Arizona for that long). Alternator tests good at Auto Zone. Maybe a battery that's on it's last legs is the cause of a lot of my problems?


Also, what is the catch code? Not the F2TA-JA part? I found another F250 at the salvage yard, same year, what looked like a 460 motor, but the serial number suggested the PCM was for a 4.9L. It was an F2TA-XXXX-ATA. I know it wasn't a 4.9L. Should I be looking at some other digits? I may go there and try that one, for $37

 

It's the alpha-numeric code that designates the calibration for your vehicle's drivetrain. For example, I have one here in front of me for a '93 4.9 w/ 5-speed and the code is "T2D1". It's the largest digits on the ID tag.

Find out what is in your truck now and then search for a replacement either locally or on-line.

That said, I too wouldn't fully trust the diagnosis from your mechanic. Lots of perfectly fine PCM's have been replaced by "mechanics" who don't otherwise know how to do proper diagnostic work.

 

Your EGR valve is causing the rough idle. If it sticks open then it will let exhaust gasses in at idle and make it run like crap at idle. Replace the EGR valve or clean it really well. Then replace the EGR sensor. Make sure you take it with you and get one with the length pin. With the aftermarket stuff it's hit or miss if the pin is long enough and it will STILL throw a code.

 

A PCM can go bad but it's not at all common, for the most part unless you live in a very corrosive environment(by the sea or where road salt is used) these things will outlive the vehicle. And based on the info you provided about dash lights dimming and intermittent drivability problems I'd bet you have corroded grounds or maybe some chaffed wires somewhere. I have had intermittent problems myself due to wiring issues, on my truck I found a wire had corroded and partially disconnected itself from the PCM power relay and as it turns out this wire was the keep-alive memory for the engine computer, which means it would lose all the little tweaks it collects over time which make the engine run smoothly. At first I replaced the PCM but that made no difference so I knew I had some other problem, so my advice is if the motor runs normally at least some of the time there's probably nothing wrong with the PCM, make repairs to eliminate any codes it presents and start looking for wiring issues.

 

Code 32: Indicates the EGR position signal from the EVP is or has been (depends on when the code is displayed) below 0.24 VDC. This would typically not indicate the EGR is stuck open. More diagnostics need to be run to verify the EVP signal output with the EGR closed as well as the output as it is opened. Invest in a cheap DVM to measure the output.

Even though your PCM is obsolete from Ford you can usually source one from an aftermarket supplier. I would not recommend doing so until you take a look at the PCM for signs of leaking capacitors or possible water damage.

PCM info from : Fuel Injection Technical Library » EEC Program Codes

 

You are correct, I use both terms from time to time.

 

This is a normal phenomenon. If your battery and alternator checked out good, then it is a none issue.

 

Computers are expensive, high-profit items, it doesn't surprise me that a repair shop wants to replace it for you - more money for them.

Here are explanations of Code 32 from Fuel Injection Technical Library » 2 Digit Self-test Codes 11-32The "intermittently failed" result is from the computer's Continuous Memory, meaning sometime during the past 50 (I think) operating cycles, the computer has detected a specific problem with that device.

This is different than the engine-off and engine-on tests, listed above that.

Perhaps the shop is trying to use this as justification to tell you that you need a new computer. Wouldn't surprise me; in fact, I'd expect it.

I agree to check the mechanical things first - remove the EGR valve (you will need a replacement gasket to reinstall it), see if it's all carboned up (and clean it out if it is). See if you can operate the thing by hand and see if it sticks. A sometimes-sticking valve can cause a sometimes-appearing engine idle problem.

If the mechanical valve seems to be operating correctly and in good working order, the next suspect is the valve's position sensor. These are just like mechanical rheostats and will wear out over time. These can be tested with an ohm meter.

Also, ensure your wiring is intact and in decent shape, and the connections are clean & good.

As said, the computer is generally the LAST thing to experience a problem. I really really really doubt the repair shop can accurately diagnose an EEC-IV computer failure without specialized testing equipment, something like a Rotunda EEC-IV computer tester:

FORD ECU Diagnostic Tool EECIV Breakout Box EEC IV 60-Pin ECU | eBay

Ya know, it's stories like this that explain why I sometimes see nice, old cars end up in the JY... shops, in their quest for your money, will blow smoke and tell you it'll cost you $2,000 to diagnose and repair your antique engine "but, step over here and take a look at the newer, more reliable replacement cars we can sell you."

 

No it is not the same thing.
The Calibration Code that is posted on the drivers door post refers to a list of many parts that was used in that truck and the part numbers and the drawing numbers of those parts.
The PCM Computer part number and drawing number is in that list of parts.
The drawing number is some time referred to as the engineering number.

The "catch code" or program code is the code for the program that is running in the computer for your truck. A another computer with the same "catch code" may or may not be the same computer. One may have diodes in the computer for the transmission and another may not but they will be running the same program with the same "catch code". Example a 1994 and 1995 truck with the same "catch code" with a E4OD transmission.

So the drawing number is the number to go by and it is the number on the computer that is F2TF-12A650-JA.
The part number or service number is not on the computer and is only used by the Ford dealer parts counter. All auto part stores and salvage yards go by the drawing number.

Your Calibration number is more than likely 1-98A-R00.
Here is your list below:


Your "catch code" or "program code" is J2C:



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