Kelly Garvey Technician/Technical Information Specialist at Kelly Garvey
Just to be fair, FS1 has been pushing to take over a fair chunk of the reman ECU market, and as a result, for certain numbers they may end up being the only game in town. I found this on multiple occasions with some Powerstroke PCMs that have been obsolete for a decade, Cardone and SMP said none in stock, Ford dealer parts room laughed, but FS1 had them. We ordered 3 ECMs from them specifically because they had it when nobody else did. 2 of them were fine and showed up in 2 or 3 weeks,(3rd was actually wrong one, had to wait till correct one was swapped) Ive also had a few car ones that were 3-4 weeks. They program the modules in advance for you offboard. Which is great in the HEY ITS PLUG AND PLAY I DONT HAVE TO SECURITY LEARN OR FLASH SOFTWARE ideal, BUT its less great if you have your own needs and just want a unit with a driver circuit that works(Some diesel guys have programmers or use custom softwares that must be reflashed anyway, so it is what it is). I had one that was defective. A different problem than the original, but definitely a defect. They asked a bunch of questions, had an "engineer" call me and review data with me to determine if the fault was in fact the ECU or the diag/install. After that, they shipped a new one out that showed up much faster than the 1st one. The original order was 3 weeks shipping, the replacement was I think 4 or 5 days. The replacement worked properly.

They are BRUTALLY slow with shipping compared to others, and I know others have had issues w warranty or returns, I know it will take awhile when I order and prepare customer for that. Minimum is usually 10 days to 2 or 3 weeks, 3-4 is not unlikely. But I can say so far, all units showed up, and worked or were warrantied and fixed trucks and cars I couldnt find the part anywhere else for. they havent done anything to make me hate them yet, Especially on the older Ford diesel units that were unobtainable elsewhere...they had them, they solved a problem and got the car delivered.

UPDATE: Last week I received a 2009 Challenger ECU. Car came in with a repeating solenoid performance issue, driver wasnt pulling down consistently (sometimes very slow and haggard to apply, wouldnt even reach within 1v of ground, though worked sometimes). Ordered replacement, LR activation now OK, but NOW had a TCC hard code (internal circuit open, reset with key cycles no driving needed). Swapped old one back, TCC code gone. New unit defective with no doubts. Called. They said they would have a tech call us. 2 days later, call and call again. Ask for manager, get put on hold, 60 seconds they hang up. Repeat a few times, finally they say never mind, return will be approved. They will email us a shipping label. Wait. 4 hours later call back. Wheres email and label? Wait. Call next day, they swear its been sent. Call and complain. Get the email. Says CLICK HERE TO PRINT LABEL. But the CLICK HERE isnt actually a link, its text that does nothing? So we have no label, no data, and no refund so far? We will keep trying. After 2 days we called LKQ and aquired a used unit which we were able to re-vin and got the car delivered. But now after 8 units at this shop, and half a dozen or more at the previous shop with only 1 defect, and no issues on my return (other than long wait times), I have seen the issues others complain about. Will see what they do in the next few days. But there is likely a loss of stars coming as customer service so far has been really awful (lying, not following up, not processing return which forced me to buy from someone else to save time and they still have our money).

Gave them a week. Still refused to process our return or ship a replacement. They always put us on hold when we call then hang up a couple of minutes later. We filed a claim with Amex, waited 3 days while Amex investigated, which also involves Amex making an effort to contact the seller and resolve with normal processses. Amex refunded our charge after 3 days indicating they could get no happiness from FS1. Stars downgraded to 1.5 only because they do sometimes have rare numbers and the 1st 10+ went OK, but any company that wont process their supposed warranty after 2 weeks, and flat out hangs up on us, doesnt answer emails or messages, and cant be held to account for the promised warranty...should not get a positive review nor will I recommend them to anyone unless you literally have tried everyone else and they are the last possible source.
Dave Wright Owner/Technician at Precision Diagnostics llc
I've had the exact same experience with FS1. You may get 8 out of 10 computers with no problem. When you call about the 2 defective ones, you get the run around. Almost no support with FS1. The last one I ordered from them took over 6 weeks to arrive. I quit dealing with them and started using Your parts source, So far, they have been a lot better to deal with.