Can we make this USED Fiat PCM work? The dealer can't! 

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As cars get older and modules become no longer supported, these component-level repairs will be the only way to keep the cars going. Hoping to see some disassembly and reassembly videos too! An awesome topic to start learning.

Really like these types of video but this one would be so much better if it included a conclusion showing if the repair was successful or not and why.👍👏

Some eeprom chips are glued to board as well like on the Mercedes me2.8 ecu’s. On those you need to twist the chip of the board once the solder is molten. This is also true when you are replacing a smart low side switch, the chip is held by the thermal compound and you have too pry the chip off the board once the solder is molten

The ST M95128W6 is a 128k Bit = 16k Byte SPI Serial EEPROM has impressive write cycles and data retention, much more than emulated EEPROM inside of the Freescale Power PC Microcontroller. Not just much more than this MCU but better than any MCU when comparing write cycles and retention. My guess, given the size of this EEPROM, is that it is only for as built data end of line calibration. I do not think it has any code like a boot loader for example. What is the round donut shaped PCB trace in the middle of the board next to a surface mount power IC? Is it an antenna? When the board is designed you first place components for input protection and filtering close to the connector. Then the power circuitry is laid out in what needs to be closest to the main connector. Then I/O conditioning is laid out, and finally the MCU circuitry. MCU traces then adopt top layer one direction and bottom layer at 90 degrees to this. So largely when looking at the top of the board traces are mostly horizontal, and if you look at the bottom of the board they should be mostly vertical. What is strange about the MCU core layout, is that there is no large ceramic or tantalum in close proximity to the MCU. You see the classic power decoupling with two smaller ceramic caps in parallel, but not a larger Tantalum in close proximity. In de-soldering the EEPROM you should mask off the MCU with Kapton tap or use an aluminum shield. A soldering shield is a thin aluminum square (2x1 inches) piece of 1/8 in sheet with a square cutout just a little larger than the IC you are replacing. You should remove the old solder on the 8 pin SOIC, and then use new solder to solder the part. The original solder may be lead free, but when repairing the board you can use eutectic tin/lead which has a much lower melting point the lead free solder.

probably never do any of this but really good information to know at least i would know where to send them for repairs which is helpful

Definitely appreciate these videos! Thank you!

I usually generously tin the pads, then hold the little guy down with a chopstick tip then apply hot air, depending on the ic type it might get a onece over with an ultrafine soldering tip for good measure. ❤

Use a silver marker or paint pen to mark the side of the chip closest to the connector or other identifying feature of the board, such as the CPU, to know which way to place the chip when going back together. If the board has a number one pin mark on it, you can put the paint mark on that corner of the chip also.

With little stuff (smaller than what you're working on), I was always happy my company had a rework group in assembly. Something 1/4 the size of that eprom and I'd walk it to them and let them perform magic on it. Nice work and it would be nice if it does work out.

Good job Keith. I do this kind of work as well in my shop. Id suggest if anyone watching that wants to get started doing this stuff to pick up an Amscope SE400-Z microscope. Its a great 'bang for your buck" starter tool for PCB work. They sell in the $200 ish range.

Fyi, brake clean is great for removing flux. Certainly cheaper than flux remover if you don't have any alcohol.

Absolutely appreciate this information. It's very interesting.

Keith, you are the man! Great video!

and you could modify a small wise grip tool to hold down the chip for soldering it

Learned some stuff, cool video.

Great info sir 👍🏿 👌 👏..cheers

The 95128 is an SPI part. It's not locked or one time programmable if the block protect bits are cleared. With the right tool you should be able to clone it in circuit. What is the part number of the ECU and we'll try it.

Dang second

Is that eprom chip the identity of the vehicle Inc the keys? Very interesting , wondered where the identity was on vehicle

Some of those modules are built to withstand WWW-III. Is there a way to convince them to come apart a little easier? I had to use my hot air gun, some screw drivers and dry wall spatulas and lots of swearing to get the one I got from eBay apart. And how about putting them back together? Where can you get the new silicon for the joints? Second question: On first glance there are three EEPROMs on that board. Two of them quite close to the MCU. Is there a chip series that is usually used for the BIOS? (computer speak) And how do I test if it worked? I have a test setup for the VW mqb (MK7 Golf and Jetta series. 2017 and thereabouts), but no other test setups. Sorry for all the questions, I'm still learning... :) Many thx for what you do! In the PNW (pacific northwest) land is way too expensive to have junk yards, so I depend on eBay. Is there a better way of getting modules?

Nice Keith, I think I heard a chuckle from Alex @ Northridge fix.

The first problem is you're working on a Fiat, most of their problems can be fixed with a gallon of gas and a match....

Good job 👍

Who programmed the EPROM? What tool was used?

Of course everyone would like to watch and learn such interesting content for free. Make more videos please 😊

What do you do when confronted with conformal coatings?

Did it work? The FIAT ECUs have both an internal and external flash. Is the external flash just where the VIN and security info get recorded? Also curious to know what the failure was of the original ECU.

can you share why the PCM was defective on the first place ? how did you know what part needed to be repaired ? and yes. if you can tell if the repair was succesful or not once in the car... very educative content. thanks for sharig.

👍

The older I get, the harder it is to see those tiny things.... let alone find it when ya blow it away with the heat gun! I need microscope goggles.

What was the issue with the original ecm?

What temp do you run your hot air gun on

Invest in some high quality tweezers ... sure $50-100 may seem like a lot, until you use them.

Watching and commenting.

Tedious work.

Fiat!!! Eww🤢

Been a mechanic & electronics tech 40yrs in OZ & this is a very basic fix ( I do phone & laptop repairs component level) & what's with the lousy microscope capture.