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Repeated DMTL Pump Failures


The dealer has replaced the DMTL pump 4 times on my 2004 BMW325. The last time the dealer checked the gas cap and smoke tested the fuel system - all OK. I do not overfill the tank. The pump has failed again and I am getting tired of taking it to the dealer for a new pump. Fortunately it is under warranty but I am sure that there is something else causing these pump failures.

Well, presumably they also have a strong interest in getting this squared away since its costing them time & money as well. In addition, they are a BMW dealer with full access to factory shop manuals and TSBs and such. So if you want a bunch of strangers on the internet who can’t see or inspect the car to help out then you need to give a lot more info.

Why is the pump continually replaced? Presumably there is a check engine light involved? Find out what the exact and specific error codes are. There won’t be one that will tell you that the pump itself is bad.

Any symptoms in addition to an engine light? What is the time frame over which you’ve had the 4 pumps installed? Have you ever been given a model of failure for one of these pumps? As in, “the pump failed because…”

Other than a smoke test, what else has been checked? Its a little motor - it needs to get power, so there is wiring involved. The computer controls it so its related to other parts sending & receiving info - also via wires.

Make sure that they have done a complete search for TSBs on the car.

If you Google “DMTL Pump” you will find half the BMW’s on the road are suffering this failure. I didn’t stay long enough to discover what function a DMTL pump performs…

Okay, it’s some kind of gas tank purge pump, part of the EVAP system…This is a concern of those who must pass an emissions test. Others can drive on…

I’d be a bit suspect of someone who replaces a part 4 times without figuring out if something is causing these to fail or whether it’s another problem that is causing them to go in the direction of the DMTL.

Just curious, but you say this is all under warranty. This means either the dealer is eating the cost of all of this, BMW corporate is involved, or you’re possibly being fed a line of BS and the pump is not being replaced; at least as many times as claimed.

A failed factory OEM part will generally have a parts warranty on it. I don’t see BMW corporate buying this job repeatedly.

Would help a lot to know what’s failing on the pump: the failure mode.

Here is some additional info. Each time the SES light comes on, but the car runs fine. I have a code reader and the code is either 27CC: DMTL - leakage, or 27CD: DMTL module failure. I have tried resetting the SES light but it comes back on in a few days, presumably when the next tank pressurization occurs. When the dealer replaces the pump, everything is fine for about 2 months. The SES light comes on and the cycle repeats. The only other service during this time was replacing the arresting valve between the 3rd and 4th pump failure.

Each time I have taken the car in, I have mentioned how quickly the part is failing. Only this last time did they do any “testing” other than reading the code and replacing the pump.

Granted the part is covered under warranty and I get to test drive some nice new BMW’s while the car is in the shop. I would like to stop being on such familiar terms with their service department.

I suspect that fuel is somehow getting into the pump and causing the failure. Any ideas what I should have the dealer check out?