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W203 - 2003 C230 Kompressor Coupe with 285,000 km
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Discussion Starter #1 (Edited)
Just bought this great old wagon and am preparing to travel into Central America.

1. CEL and Fault Codes
Can't find the trouble/fault code list for the 89 300TE (CA version). It has the SMALL connector beside the battery with the flashing LED (as compared to past M104's I've owned with the larger connector in the same location). Would appreciate list of codes and instructions to read/reset (since it's logic seems different than later ones, with LED constantly on when key in position 2).

2. Cold Start Hesitation
Been trying to solve a cold hesitation problem over the past few weeks.

Car symptoms... CEL not lit. When cool (Temp gauge reading 40C or less), pressing the accelerator does little to nothing. Doesn't really die out, but doesn't accelerate, either. Seems fine when up to normal operating temp (though I must admit I'm not used to the transmission starting out in 2nd gear and having far less torque than in later M103 or M104 300E's I've owned).

OVP relay seems ok (though connecting a loose cable at it's base turned off the ABS light). I read in the forums that air/fuel adjustment may be necessary. Also, I've read that the temperature sensor may be faulty.

There's no odor of gasoline anywhere. Fuel consumption averaged 19 mpg over last 1000 miles of mostly city driving, much of it with A/C. Have changed fuel filter (and done oil and transmission service). Emissions test easily passed. Neutral Safety Switch is faulty, I guess, since it will only start in neutral, but I'm thinking of leaving it that way as an additional security feature (instead of a kill switch) for 3rd world travel. Not sure where to go next.

Should I just swap out the temp sensor with one from the junkyard and see if that fixes it, or force myself to learn how to use a multi-meter and check the resistance? And figure out how to adjust the duty cycle? I'm a complete moron at things electrical, and frankly, not much better with things mechanical, though I'm learning.

3. Climate Control Weirdness
Can't get any airflow to the defroster vents when defrost button pushed, though the heat is definitely on and the fan is at max speed. Also, the A/C center vents seem to have a mind of their own -- they open when coasting or with very low engine load, but audibly snap closed upon even gentle acceleration.

Your ideas and suggestions greatly welcomed. I love these forums, as I've bought and sold a bunch of Mercedes in recent years... always seem to find the right answers, but I'm stumped on these ones.
 

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W203 - 2003 C230 Kompressor Coupe with 285,000 km
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6 Posts
Discussion Starter #2
update

Cold Hesitation Update:
I found a multimeter and tested the Temperature Sensor at the back of the head. Seems good. With the engine warm at 80C, the resistance is 275 ohms (with the dial set at "2000" to obtain reading) and with the engine cold at 20C, the resistance reads "2.5" with the dial set at "20k" to obtain the reading. Even though the fuses look good in the OVP, I'm going to swap them for other ones just to see if that does it.

If that doesn't work, I guess I'm on to picking up a new multimeter to check the Duty Cycle.

As an aside, as a result of all the spraying and cleaning done underneath while servicing the transmission, the Neutral Safety Switch decided to start working again all by itself!
 

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89 300E; 00 E320
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You may want to get a new OVP as they are sometimes bad even if fuse on top looks good. Would not hurt to have a spare if you are out of the country. Maybe the guys here could provide more tips for your travels that will add some automotive security. Travel Kit

Not sure if you can check the duty cycle on the CA version at the X11 connector; so you may need to grab voltage at O2 sensor. Here are some references for the fuel mixture adjustment and O2/lambda sensor:

http://www.landiss.com/mixture.htm

Fuel mixture adjustment

http://www.benzworld.org/forums/w124-e-ce-d-td-class/1231077-fuel-mixture-adjustment-2.html#post2481615

http://www.benzworld.org/forums/w124-e-ce-d-td-class/1231077-fuel-mixture-adjustment-4.html#post4454281

O2/lambda sensor testing
 
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