Fuel Quantity Indicator Failure
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From: Fallon, NV
BMW and Mercedes
Yeah, I don't want to think about how many things failed > 1 time while under warranty. It's ok though.....I really do like the car, just the electronics are well under par for what they should be for such an (originally) expensive car
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From: SF Bay Area
1999 C43
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From: Fallon, NV
BMW and Mercedes
So does anyone have the HVAC codes for the w202, or do I just assume they are the same for the w208? For quick reference, it appears my in car temp = 88, while bumper temp = 106, L side heater core = 99, evaporator temp sensor = 162, engine coolant temp = 210, freon pressure = 11.8 (whatever units they use), freon temp = 96, software and hardware versions 03 and 03. This is all from the list on the link, recorded today after a 15 minute drive and idling for a couple minutes while I figured out the switchology for the HVAC diagnostics.... what do you all think?
To update my situation, the A/c is still working, i.e it still blows ice cold on first start up. Oddly enough, no matter how long it takes me to get to this certain spot on my drive to work (after 1st start) I can feel the a/c disengage at almost the exact same spot every time. After that, no matter what I do it will not re-engage. At first it blows luke-cold (if thats a word haha), then slowly just gets rather warm. Also, it almost immediately gets really humid. If I continue running the "a/c" it will be muggy in the car and it smells either like stank air from the ducts, or possibly even the slight smell of engine coolant. Thoughts?
To update my situation, the A/c is still working, i.e it still blows ice cold on first start up. Oddly enough, no matter how long it takes me to get to this certain spot on my drive to work (after 1st start) I can feel the a/c disengage at almost the exact same spot every time. After that, no matter what I do it will not re-engage. At first it blows luke-cold (if thats a word haha), then slowly just gets rather warm. Also, it almost immediately gets really humid. If I continue running the "a/c" it will be muggy in the car and it smells either like stank air from the ducts, or possibly even the slight smell of engine coolant. Thoughts?
Last edited by FLYNAVY; Jul 1, 2008 at 07:53 PM.
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From: SCV SoCal
2002 CLK430
Sounds like you evaporator sensor may be broken. It should be close to the in-car temperature sensor while the A/C is off, and a lot lower while the A/C is on. I just tested mine in my 92˚ garage. After a few minutes at idle and a little higher (1000 RPM at most), my evaporator sensor read 40˚. The left and right heater cores were about 5˚ higher. The real test is the vent temperature. Using my infrared, I saw 29˚ at the center vents and 34 at the outer vents.
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1999 C43 AMG
yay....thats basically the average then. Not to sound cheap, but I'm not sure why MB can't make a car that doesn't charge you 800-1000 bones every 10 months for random electrical gremlins. And on top of this, I have a phantom A/C sensor failure....like it refuses to turn on the cold A/C air on occaison, and after shutdown and re-start its all good. Man I need to sell this piece of ****
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From: Fallon, NV
BMW and Mercedes
SAVE YOUR DOUGH!! Happy to report that after the 3rd bottle of injection cleaner my fuel gauge is definitely working and I'm sure it's as accurate as it ever was...let the needle drop as low as I have so far, half-way into the orange, and it took 14.5 gal. Seems about as close as it's gonna get. No more reading empty on a full tank and no more sudden drops from full to half.
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From: Fallon, NV
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Sounds like you evaporator sensor may be broken. It should be close to the in-car temperature sensor while the A/C is off, and a lot lower while the A/C is on. I just tested mine in my 92˚ garage. After a few minutes at idle and a little higher (1000 RPM at most), my evaporator sensor read 40˚. The left and right heater cores were about 5˚ higher. The real test is the vent temperature. Using my infrared, I saw 29˚ at the center vents and 34 at the outer vents.
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From: SCV SoCal
2002 CLK430
I'm not an AC tech, so someone (anyone) can feel free to tell me I have no idea what I'm talking about, but here is *my* understanding of what's happening: The faulty evap sensor is leading to the system getting too cold and icing up (To prevent icing, the compressor is supposed to cycle off at certain temps. It trusts those lying faulty sensors for that temperature info). Some other sensor eventually shouts, "Icebergs dead ahead captain!!!", and the compressor shuts down. At some point (very quickly due to the 100 degree outside air that's entering the system), the ice melts and your interior is as humid as Manhattan in August. Thrill said the sensor swap took 30 seconds. Although, if I remember correctly, he had threads on multiple forums because he had trouble finding it.
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Alright, this really sounds like the exact symptoms I am experiencing. It definitely occurs w/n a minute + a few seconds from cold start, each and every time. Starts ice cold like I said, and then suddenly stops, begins to blow warm air, and it gets really humid. Sooooo, I ordered the new evap temp sensor ($38 ) and I've got a couple more questions:
1) How do I access the underdash area? I've never poked around down there, and I'd rather ask and not break anything, than make it open up and end up damaging something, trim-wise
2) Am I able to replace the sensor w/o opening up the refrigerant loop? I.e do I need to evacuate the system first, and then re-charge, or does it just swap out?
Thanks again for all the help guys, really hoping this is the problem!
) and I've got a couple more questions:1) How do I access the underdash area? I've never poked around down there, and I'd rather ask and not break anything, than make it open up and end up damaging something, trim-wise
2) Am I able to replace the sensor w/o opening up the refrigerant loop? I.e do I need to evacuate the system first, and then re-charge, or does it just swap out?
Thanks again for all the help guys, really hoping this is the problem!
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From: Fallon, NV
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From: SCV SoCal
2002 CLK430
Found the location, you get to it through the driver's side footwell. As I suspected, it's the same as the CLK. It's the left hand photos, B10/6x1
Digging up the R&R next . . . . . .
Digging up the R&R next . . . . . .
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From: SCV SoCal
2002 CLK430
The WIS is a pain to find things on. Once found, it make sense, but finding things is tough . . . . . . and I couldn't find the R&R in the WIS, so I used the CLK DVD . . . . . which allowed me to see that I don't have a procedure, but I can see where it's located.
Using Thrill's photo, while laying on your back and looking up, this is what you'll see:
The yellow circle is the top of the accellerator pedal arm.
The red circle to the right is the evaporator temperature sensor. If you have the new part, the prong goes into the heater housing. The housing is hollow/no liquid inside. Per Thrill, the new sensor is supposed to be an upgraded part. Unclip the electrical plug and remove the sensor. pull? twist? Post back and let me know how it comes out.
Using Thrill's photo, while laying on your back and looking up, this is what you'll see:
The yellow circle is the top of the accellerator pedal arm.
The red circle to the right is the evaporator temperature sensor. If you have the new part, the prong goes into the heater housing. The housing is hollow/no liquid inside. Per Thrill, the new sensor is supposed to be an upgraded part. Unclip the electrical plug and remove the sensor. pull? twist? Post back and let me know how it comes out.
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From: Fallon, NV
BMW and Mercedes
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From: SCV SoCal
2002 CLK430
1) With the dealer charging $175 for a part that has a dealer MSRP of $51, very few things are "free".
2) For a dealer to claim that the install was free, it must be a very easy to do.
Enjoy the cold air!
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'98 C43 AMG. Obsidian Blk w/2 tone slvr/blk interior
i have been saying evap temp sensor for a month now!
i told you i was all too familiar with the symptoms. the dealer replaced mine with no labor, they charged me 120. and i got to drive a loaner for 2 days.. pretty good deal.
i told you i was all too familiar with the symptoms. the dealer replaced mine with no labor, they charged me 120. and i got to drive a loaner for 2 days.. pretty good deal.
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Indeed, I just wanted to make sure (or at least be pretty confident) before I got to it
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From: Fallon, NV
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Alright guys, received the new sensor this afternoon....just getting ready to head out to the garage and swap it in, now that the sun is going down and the temp is under 90 deg 
What do you guys think....am I going to inadvertently open up the refrigerant loop? Also, are the fasteners holding in the kick panel above the pedals in obvious locations, or is there a trick to removing it? Thanks again for all the help!
What do you guys think....am I going to inadvertently open up the refrigerant loop? Also, are the fasteners holding in the kick panel above the pedals in obvious locations, or is there a trick to removing it? Thanks again for all the help!
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From: Fallon, NV
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Update: Yeaaaaaaahhhhhh, swapped out the sensor in prob like 20 mins, put everything back together, fired it up, took it out for a spin and cycled through the different modes and temperatures of the CC system and I'm glad to report it blows ice cold again w/o any shut downs. If anyone has this problem in the future, I too highly recommend doing this before you have a "professional" look at it. Thanks for the help everyone!
Oh yeah, what product would you recommend using to clean my fuel system and try to get the gas quantity indicator reading properly again?
Oh yeah, what product would you recommend using to clean my fuel system and try to get the gas quantity indicator reading properly again?
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From: SCV SoCal
2002 CLK430
You just saved a couple of hundred dollars and of even greater imporatnce, you've demonstrated that regular people can work on these highly technical cars. If you had to do it again, how long would it take? Ten minutes? Five?
Chevron Techron concentrate or Chevron Pro Gard are good fuel cleaners, but I don't know if this will correct the fuel level sensor problem.
Chevron Techron concentrate or Chevron Pro Gard are good fuel cleaners, but I don't know if this will correct the fuel level sensor problem.
Thread Starter
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From: Fallon, NV
BMW and Mercedes
You just saved a couple of hundred dollars and of even greater imporatnce, you've demonstrated that regular people can work on these highly technical cars. If you had to do it again, how long would it take? Ten minutes? Five?
Chevron Techron concentrate or Chevron Pro Gard are good fuel cleaners, but I don't know if this will correct the fuel level sensor problem.
Chevron Techron concentrate or Chevron Pro Gard are good fuel cleaners, but I don't know if this will correct the fuel level sensor problem.
