Diesel Control

Fernando DeMoura
May 2019

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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Flash code 53 is 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

www.dieselcontrolservice.com