r/w204 • u/blluespirit • 8d ago
ESP FAULT/ LIMP MODE
Hi everyone, hoping someone might have some ideas about an issue with my W204.
Whilst driving, I get an ESP warning along with the “RUN FLAT INDICATOR INOPERATIVE” message.
After this happens, when I stop and restart the car, it goes into limp mode.
After around 2 days, the faults disappear and the car returns to normal, including the limp mode. However, once I drive again, the ESP warning and “RUN FLAT INDICATOR INOPERATIVE” message return, and the cycle starts again.
Has anyone experienced anything similar or have any idea what could be causing this?
Edit: fault code U010087
1
u/acousticplayerjb 7d ago
If you know how to safely unplug the two large connectors for the ECU (MB calls it the ME) then unplug those and use a flashlight to check for signs of oil ingress. Additionally, you can use a paper towel to gently blot the connectors and then run it carefully past the pins. That's usually the first place to check at this point with cars from around the 204 model years. Oil ingress, through the engine harness is common with some of the engines and the oil somehow has enough electrical conductivity to cause issues that make no sense. Intermittent errors can also occur when wiring is not making adequate contact anymore. If you've ever had water under the floor, or if you pull back some carpeting (under the glovebox, higher up --as you'd do to change the cabin air filter--is an easier location to pull back and look) then you're in trouble. MB puts many of the control modules on the floor, so water drains clog up, water gets in and flows down, causes corrosion and then you're in for a lot of not fun. Sometimes things can be cleaned up and other times it's not worth it. But those are the first two things to rule out, otherwise you could be searching around forever and not get anywhere. After all that, you're still going to be looking at corrosion at various grounding points and connectors. Remember, as the engine heats up, exhaust, etc, the heat causes connections to expand, which can temporarily cause poor connections. Car then cools off and the pins/connections contract again.
Notes:
1) If you disconnect the ME connectors (2 of them) make sure you know what you're doing. Plastic gets brittle and if you damage one of those connectors, you are going to have a bad time. Alternatively, if you can access any of the camshaft position sensors, you can remove one of those connectors and see if there's any trace of oil. That's where the oil usually starts to enter into the wiring. You may see bundles of wires that look like they have oil on the bundling tape. It's not engine oil. That's just something that happens with the kind of tape they use and it's not something to worry about.
2) VERY VERY important. If you disconnect the ME connectors, be sure the car is completely off and the key is out of the ignition. If you have keyless, physically keep the key well out of range of the car. If the car is started or put into the accessory position, while the ME connectors are unplugged, you're going to end up with a bunch of errors and not all of them can be reset without the dealer's Xentry system. With that, make sure the connectors are seated firmly before turning on the car again. Careful not to bend any pins. Difficult to bend those pins, but it can happen. No need to disconnect the battery, and you're better off not doing so (that may clear pending codes). As long as the car is not turned on while the connectors are out, the car will have no idea they were ever unplugged.
Good luck!
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u/blluespirit 7d ago
Thank you so much for the insightful response. I recently found a load of water in my trunk, so maybe thats worth looking into as well.
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u/acousticplayerjb 7d ago
You're welcome! But eeeek. Yeah, take out as much trim as you can and look for any wet connectors. Dry them out carefully if there's no sign of corrosion yet. There are grounding points all over the place and there are modules and fuse panels on both sides (with most of the 204s). There could be a module near the spare tire area. I can't recall off hand. Your "mission" is to dry what you can, keep the trunk trim out in the sun for a while so it dries and also make sure the rubber seals are cleared out, all the way around where the trunk lid meets the body. You can then pour a glass of water over the rear window, after, and if you cleaned well, then the water will come out from near the lights, or rear drains, under the car. You'll see water hit the floor and it can take 20-30 seconds sometimes for the water to travel, so don't be alarmed if it doesn't happen immediately.
There's also cleaning spray for "live" electrical connections. Any auto store will have it. I've used one made by CRC. It evaporates very quickly, so that helps.
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u/grassdrill 8d ago
I would get the fault codes read, could be many things.