hi i just bought a 1999 c280. i had a check engine light on and had autozone scan it. they said it was code 0170 left bank fuel trim malfunction. the other code was 0173 right bank fuel trim malfunction. i called the dealer and asked if any of their techs had seen these codes often. they told me to change the fuel filter and or the plugs, i did both but no difference. if anyone has any info at all i would greatly appreciate it. thanks

 

the oxygen sensor reading is too lean.

check the oxygen sensor, air leak, air in fuel line, or adjust the ignition to slightly enrich. maybe the throttle valve is very dirty.

 

Follow sleepwalker advise. But I have a question, when you change the filter and plugs. When you started the car the check light was still on? Try having the code erased and see if it comes back after a while. These codes do go away, the light that is after so many starts, but the fault codes doesn't, so if the light is still one have the bad codes erased and see what happens. I've had the same problem, once is was an O2 sensor and the other the MAS. I guess to just asked Mercedes about the code numbers? Probably you should have had them read the codes also, not all code readers are equal, I found out.

 

thankyou for the info. one other question is how do you adjust the ignition? i cleaned the throttle body and had the code cleared. next day same two codes. checked for air intake leak and found none. also checked fuel pressure, found 45psi engine off key on. and 58psi engine running. any info appreciated thankyou.

 

try this

[IMG]local://upfiles/1/9BDF0DC0FA9643A4AD0A292A40AE44DE.jpg[/IMG]

 

>.

[IMG]local://upfiles/1/06722CB396064E04BA6EBAECEDF54774.jpg[/IMG]