Brian Darby

It's me again 04 CL K320 W209 with the cooling fan on high. This happened a few years ago after my wife hit a raccoon and they replaced the fan and the module and it stopped. I went with OEM Mercedes parts, because I do that with all my vehicles. the other day my wife gets in the car and starts it and then a coolant light came on briefly and then it went into take it to the shop mode.
I took it to my guy and he said he had to hook up the battery charger to it to get the computer to go through the testing that it needed. it seemed to start fine. we are trying to sell this vehicle if I can't get it fixed reasonably. I need help with this car, it only has 57000 miles on it

it makes me think there's a bad ground somewhere, they are telling me that the computer is telling the fan to go on high. how can the computer work fine except for one aspect of it.

between this and the SRS module being on for the past two years I don't know what to do

Rudeney

The fan goes on high like that for one of two reasons - either it can't talk to the ECU, or the ECU can't get a reading on the engine temperature. The former could be a bad ECU (but doubtful since the engine operates) or bad fan controller (part of the fan motor). The latter could be a bad sensor.

insame1

I bet this is the answer to your problem. These cars a very particular about voltage and will do very odd things when it isn't right.

Brian Darby

I just picked up the car and had the battery replaced it was from 2011, so it was bad, he wouldn't give me the codes but he told me the first code was replace module, and the rest were just seatbelt and occupancy sensors. I will purchase the carsoft and let you know what I come up with. on another note I hope the battery issue fixes my coolant fan problem but I'm not sure how many times the ignition has to cycle before it resets itself. Will that scanner allow me to clear the code associated with the cooling fan also?

Rudeney

Yes iCarsoft can read and clear codes form all the car's various systems. if low voltage was the cause of the fan problem, then it should resolve itself immediately, although the MIL may remain illuminated for 5-10 start/stop cycles. If the fan is still on high, then you still have an issue. My SL550 started doing that, and would even keep running for several minutes after shutting off the engine. I fiddled around with the wiring at the temp sensor and it has not one it since then.

Brian Darby

Well I got the unit in and did my scanning and here is what I have on the fan problem, I have cleared them and they come right back.

P2073-004
P2073-004
then after clear
P2073-001
P2073-064

I will post the airbag codes in that forum
Some modules I would get a communication error when I tried to read or clear codes

Rudeney

This points to a wiring problem with the fan. I'd unplug its connector and clean the contacts and see if that helps. SDS states specifically that this is not a bad fan, but it does have some other steps to go through for thoroughly testing its communication with the ECU that you would not be able to without SDS and it's additional "breakout box" tool that allows you to probe and engage various ECU circuitry.

Brian Darby

It seems like the car has multiple communication issues, so where can I go in Florida with someone that has the knowledge to diagnoses electrical issues without telling me that I need to replace every module

Brian Darby

Also is this tied to the coolant Warning light being on?

Rudeney

The fan failing to communicate with the ECU triggers the coolant warning.

Brian Darby

Can you tell me where the ECM is located? is it up by the driver side hood hinge underneath that panel with the fuses and relays. I've heard there could be wiring issues between the fan and the ECM and that there is a replacement harness update

Brian Darby

also the second code when I do research on it says the mass airflow sensor

P2073-064

Rudeney

The ECU is in the E-box, which is on the driver's side, under the hood hinge, with the fuse panel/SAM.