My 1996 C-280 Check Engine Light came on the other day. Car is driving fine, don't notice any driveability problems. Took it to Autozone for the codes to be read. The only code given was a 0170, something about fuel trim out of range. What could cause this? The only other time that it has given a code was when the wife ran it out of gas, coincidentally, she confessed to running it very low just the other day, could this be related? Any help would be appreciated. Thanks.

Fuel trim means that the fuel computer ISN'T adjusting the mixture! LOW fuel pressure, vacuum leaks, or a bad air mass sensor are the most likely causes!!

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Thanks for the info.

Now some more questions.

Do you know what kind of fuel pressure readings I should see if I check it? Also, I don't know, is there a service port on the fuel rail where I can hook my pressure gage, or do I have to get creative and come up with something on my own? Thanks.

there is a service port on the fuel rail to connect a fuel pressure guage(same size as an old a/c charge hose R12). The fuel pressure should be around 55psi at idle.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

My 97 C230 had the check engine light actuate. Cause was that I had run the car low on fuel... [fuel warning light was on]