Diesel Control
Memory failure is a common issue in any computer that’s over 20 years old, DDEC ECMs are no exception. One of the calls I got last month about a 2012 reman DDEC with a memory problem. The conversation started off as many do. “The dealer flashed my ECM and now it has a code 53 and they’re telling me I need a new ECM. How much and how long till I can get this fixed?” I replied the way I usually do to that question. “I could tell you that if I knew what was damaged. How old is the box”? “It’s a 2012 reman” “Ok…So they’ve either downloaded a damaged program or the ECM has hardware damage so it’s either going to be an easy fix or a fairly complex repair.” The owner of that DDEC ended up sending it to me and it wasn’t until I actually opened up his box that I realized that I was wrong about what I told him.
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activated when a checksum values don’t match.
A checksum works like a watchdog that looks for damage to the program.
Downloading a damaged program or downloading a good program into an ecm with
failing or damaged memory components will activate flash code 53. When code 53
goes active the ECM will try to run a backup copy of the program. This usually
buys a little time before the damaged program deteriorates enough to cause
drivability problems or a no start problem.
When a tech or a would-be ECM rebuilder asks me if reflashing the ecm
will fix a code 53 problem I tell them it will if and only if they’ve just
flashed in a damaged program. Otherwise they’re looking at a hardware issue and
if they try to reflash it anyways they’re just going to be making more work for
me. Why? The erase functions on memory are usually the last to fail. The first
to fail are the write functions. Before new data is transferred to an ECM
during a reflash the old data must be erased.
That part is almost always successful but when new data is being written
to the damaged memory the data doesn’t save. To make things worse reflashing
usually erases the backup program so now the program that got the truck to the
shop is gone and the truck won’t start. Those of you who’ve done it know what
happens next. Someone’s going to get reamed out and it’s usually going to be one
of the new guys. The shop foreman will say he didn’t disconnect the battery
cables or something, but it wasn’t his fault. It was the guy with the laptop
that bricked the box.
Anyways…The first
thing I did when I got this 2012 reman DDEC IV on my test bench is I backed it
up. The next thing I did was reflash it and guess what? It didn’t work. So out
comes the T10 Torx driver, then the perfectly clean service plate and…I find
myself looking at an oxidized 1998 Motorola P23519307 DDEC IV with all its
original parts save the battery. If I had known that inside this 2012 box was
one of the oldest DDEC IVs I’ve seen I would’ve opened it up as soon as I got
my hands on it. This box had memory components in it that were made by a
manufacture that hadn’t been in business in 15 years. I’ve never seen a DMR reman
box leave parts this old in one of their boxes and I’m still not convinced this
is a genuine DMR part. The owner said he paid his freightliner dealer $2400 for
it and this was the third DDEC ECM he had bought from them because the other
two had the same problem this one did. 48 hours and $450 later he was back on
the road with new memory. He told me his idling was smoother and isn’t getting
any more fault codes.
Written by Fernando DeMoura, Diesel Control Service
Phone 412-327-9400