I've been complaining about how My '99 F-250 SuperDuty 6.8 V-10 runs 'n shifts ****ty ever-since FINALLY (for all the MUD I had to clean-away for the kid I bought It from likely having submarined It... ; ) getting it Road-Ready enough to actually DRIVE... : ?

Including recently replacing the MAF SENSOR for MUD CONTAMINATION (that I simply couldn't clean-away well-enough... ; ) for It rather consistantly producing BARO readings @ < 40 Hz. ~ thus rather indicating I'm some 5500 feet HIGHER in elevation than True ~ causing it to run LEAN pretty-much across-the-board... : ?

And though the Truck does run & shift a little-better for having replaced It, for whatever reason(s) It still quickly recalculates to higher elevations...the re-calculates BACK to >/= 55 Hz. with a couple 'r three good STOMPS on the throttle ~ which is how One is to re-set It after being-driven at Higher elevations... : ?

I've also noticed the Speedo reads 'bout 5 mph higher than the VSS (Vehicle Speed Sensor) rather displays on the Scan-Tool... : ?

So I perform My first KOEO "Self-Test" and whereas DTC P-0605 "ROM ERROR" comes-up ~ Mitchell/All-Data says "REPLACE PCM" ~ Really : ?

The Local Fo.Mo.Co. dealer wants $150 to "FLASH" It...otherwise seeing both "Stock" and "Performance" PCM's @ +/- $300 Bucks... : ?

Who's "Been-There ~ Done-That"...Please speak-Up, Thanks!
<!--= 40 Hz.) than TRUE of My +/- 1200 ft. above MSL elevation-location...though it will "Re-Calculate" somewhat properly with a good-stomp 'er three on the Throttle...which supposedly "Re-Sets" It back to "ZERO MSL" (59 Hz. = "Sea Level")

So I perform My first KOEO "Self-Test" and whereas DTC P-0605 "ROM ERROR" comes-up ~ Mitchell/All-Data says "REPLACE PCM" ~ Really : ?-->

 

Not sure this is helpful but the Actron site for DTC's shows that code being: P0605
Powertrain Control Module Read Only Memory Test Malfunction Not sure that's instant death, someone else here might know a bit more though.

 

Has the PCM ever been flashed with any performance tuner or had an add-on installed?

If so, that is why the ROM checksum is failing its selftest.

 

Thank You for the replies!

Yep, I'll clear-code and perform KOEO Self-Test ~ and it will re-set the P-0605 DTC every time ~ And "REPLACE PCM" is the recommendation... : ?

For several reasons I thought It may have been "CHIPPED", so in the endeavor of returning it BACK to "Stock" I removed the PCM to check 'n see...and because it appeared to have never had one installed (because the silicon remains intact on the contact-pins) now I think it may have rather been "FLASHED" at one-time... : ?

Previous Owner(s) did a lot of stuff to It, such as Re-Man Eng. & Trans., K&N Cold Air Intake, (wrong/cheap) Lift-Kits, Brush-Guard, Knurff-Bars, "Blacked-Out" and "Bed-Linered" windows, lighting-lens, & trim, etc., that indicate (IMHO) they'd have likely tried improving performance as-such too...the MAF is persistently recalculating to a higher elevation than I'm actually at, the VSS data-stream reads at-least 5 mph slower than the Speedometer indicates I'm traveling, and - unless I drive it with ONLY My Big-Toe - under hard-acceleration It only wants to down-shift TWO gears, revs like a Banshee, and then up-shift late ~ makin' Me feel like I'm driving a freakin' HOT Water-Bed... : ?

Now I really like the "LINES" of this particular series Ford Truck...but this one in particular is certainly NOT serving My "Needs", not the least-of-which were It's candidacy as a "Fummins Conversion" for NOT being clean enough to warrant the $$$ & Work involved in making IT One, much-less having the ZF-6 Manual Trans I now KNOW I'd rather prefer over the 4R100 Automatic... : ?

That's My fault for getting impatient about waiting for just the right Truck...then having gone-seen It Two-Counties away a mile down a dark Country Road on a Moon-less night with only a "Head-Lamp" to inspect It...only to MISS what I then came to see of the condition of the Interior, Body, & Paint THE FOLLOWING DAY... : ?

I'm tellin' Ya this in no-uncertain terms ~ Were It a "Date" I'd have chewed My arm-off!

But I've put a LOT of time & materials into making It "Road Ready" since ~ and can't-help think about all-that every time I figure selling It to move-on...DECISIONS : ?

 

A flash will not (usually) cause a ROM checksum error, as the reflash data is correctly checksummed by the tuner company or custom tuner company.

It might have been an interrupted flash.

I'd try to find another PCM from a junkyard. They aren't hard to find. I found one for my '97 Cougar in a junkyard right in my home town, through Car-Part.com--Used Auto Parts Market

Find the calibration code on the PCM and look it up at that web site.