Battery replacement – DDEC IV only (No internal battery in a DDEC III)
Back in 2008 if a DDEC IV or DDEC V had an active fault code 46 (SID 214): “RTC backup battery low” it was believed that the ECM had to be replaced. I had to tell the owner of that ECM that he needed to replace it to correct the problem and he was looking at about $2,000 dollars. I hated giving out that bad news and I hated not being able to offer any other option. So I took some time to look into the problem.
After dissecting several cores I found that fault code 46 went active when the voltage from the internal battery to the RTC (Real Time Clock) circuit dropped below 2 volts. As it turned out an active RTC fault was really fairly minor problem but should be taken as a warning. Want to know what’s a lot worse than a dead internal battery in an ECM? A dead internal battery leaking acid…all over the circuit board.
Back in 2009 I didn’t have a source for the OE batteries. Instead, I used large coin cell batteries such as those found in key fobs. That procedure bought the owners of DDECs with this problem a few more years but nothing close to the life of the original battery. Besides short life these coin cell batteries had another problem. Sometimes the battery itself would pop out of it’s holder and bounce around the inside of the ECM until it shorted and shut the truck down. Coin cell and other consumer grade batteries are not anything like the industrial OE batteries used in these ECMs. Ever go to change the batteries in a Maglite flashlight and find the cap jammed and white oxidation around the batteries? It didn’t take those flashlight batteries 20 years to get like that. … on are more likely to leak than the OE batteries. I’ll never install a coin cell or camera battery again in a DDEC because I know the problems that come with the cheaper batteries aren’t worth it. We only use the OE batteries. If the ECM is not connected to a 12 or 24 volt unswitched supply and instead sits in a shelf somewhere in a parts room the internal battery life will be about 10 years. If the DDEC is kept hooked up to a truck and that trucks batteries are good the internal battery life will exceed 10 years.
**The internal battery in DDEC IV ecms is not the only part that fails over time. This service includes the replacement of all other parts other than memory that typically fail within a 10-15 year period.
Most original 1998-2002 DDEC IVs have and internal battery that’s low or dead.
A DDEC IV will still run with a dead internal battery. The real problems start when that battery starts leaking.
Some DDEC repair shops use key fob or camera batteries as replacements but consumer grade batteries like those are not designed for the vibration and the thermal cycles the OE battery was designed to endure. Some other shops cuts up soup can lids and use the strips to hold down DDEC batteries.
DDEC III and DDEC IV memory replacement
Estimated cost for this service: $500 (includes reprogramming if done before the program is too corrupt to start the engine.)
Estimated repair time: 24 hours
The DDEC III doesn’t have RTC battery issues like the DDEC IV and DDEC V. The weak link in a DDEC III are the memory. When the diagnostic code for Nonvolatile memory failure or Nonvolatile memory data incorrect (Flash 53) pops up most technicians believe an ECMs memory chip has failed and it’s time to core it. Sometimes they’re right and fuel and oil damaged a trace or component in digital processes but most of the time the these DDEC IIIs are ready to be put back into service after the memory and a few other parts are replaced. If Memory failures and data corruption is allowed to go on it will get worse over time and eventually progress to a no start issue.
If those two fault codes are active and cannot be cleared then it’s not too late to save the program in your DDEC III. If you get it here soon we can probably recover it, check it for corruption then install it into the new memory
Sometimes it’s just bad parts and sometimes it’s damaged parts and damaged circuit board. This DDEC III will need more than memory to get it running again.