ebsprintin
Veteran Expediter
The past two years I've had a recurring check engine light that kicked out no error codes or error codes that made no sense. It finally came on hard and steady in April of this year, and the error code indicated that the diesel particulate filter was failing to regenerate. Problem was that the dpf looked clean through a borescope and didn't have any backpressure when air was blown through it. The vehicle was going in for body damage repair, so I told the mercedes dealership to dig into the vehicle and find the problem. Mercedes engineers in US and Germany were involved, and still a firm solution couldn't be figured out from the vehicle's data, so it became a guessing game. My choices were to replace either the diesel particulate or the engine control module. If one didn't fix the problem then try the other. The engineers leaned towards starting with the dpf, but the mechanic and I decided to start with the ecm.
The final prognosis is we don't know exactly what fixed the vehicle though it appeared to probably be in the ecm. When the tech first replaced the ecm, it wouldn't mate with the vehicle using the automatic mating process. Vehicle wouldn't even start. The manual doesn't say this, but the engineers then said that this sometimes happens to "older dodge" sprinters, so the solution is to manually mate the computer to the vehicle. The tech step by step, manually connected the ecm to the vehicle (this manual process isn't a physical process, but it is still time consuming compared to plug-and-play). Everything mated except the electronic throttle control. The dealership tech disconnected the throttle control, plugged in a new one "still in the box", and let the ecm learn the parameters of the new throttle control. The tech then disconnected the "still in the box" throttle control and reconnected the still installed old throttle control and everything worked. Half of what the tech did was contrary to what Mecedes was telling him to try. I ended up only having to buy the one new ecm and one minor emissions valve that was changed out earlier. There is even the chance that if we had tried to manually remate the original ecm, the original problem might have gone away, but since the new one was mated to my vehicle, I owned it--no returns, so we weren't going to continue playing with something that is now working. $2900 total for me while the dealership absorbed an extra 15 hours of diagnostics that they are going to claim from Mercedes.
I'm not sure if there is a moral to this story. Just beware that what makes sense might not be the case when dealing with high technology. And beware of throwing parts at an unclear problem. Following other routes I could have easily been sitting on a $10,000 repair bill on top of one month out of service.
For those who don't know the vehicle, it is a 2007 Dodge Sprinter 2500.
eb
The final prognosis is we don't know exactly what fixed the vehicle though it appeared to probably be in the ecm. When the tech first replaced the ecm, it wouldn't mate with the vehicle using the automatic mating process. Vehicle wouldn't even start. The manual doesn't say this, but the engineers then said that this sometimes happens to "older dodge" sprinters, so the solution is to manually mate the computer to the vehicle. The tech step by step, manually connected the ecm to the vehicle (this manual process isn't a physical process, but it is still time consuming compared to plug-and-play). Everything mated except the electronic throttle control. The dealership tech disconnected the throttle control, plugged in a new one "still in the box", and let the ecm learn the parameters of the new throttle control. The tech then disconnected the "still in the box" throttle control and reconnected the still installed old throttle control and everything worked. Half of what the tech did was contrary to what Mecedes was telling him to try. I ended up only having to buy the one new ecm and one minor emissions valve that was changed out earlier. There is even the chance that if we had tried to manually remate the original ecm, the original problem might have gone away, but since the new one was mated to my vehicle, I owned it--no returns, so we weren't going to continue playing with something that is now working. $2900 total for me while the dealership absorbed an extra 15 hours of diagnostics that they are going to claim from Mercedes.
I'm not sure if there is a moral to this story. Just beware that what makes sense might not be the case when dealing with high technology. And beware of throwing parts at an unclear problem. Following other routes I could have easily been sitting on a $10,000 repair bill on top of one month out of service.
For those who don't know the vehicle, it is a 2007 Dodge Sprinter 2500.
eb
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