I have a 96 Mercedes E320 that has had a checkengine light on for almost a year now. Car has been running smooth with no problems. I have to take the car to get it emissioned.A few weeks ago the car started to idle and run roughly. I pulled over and inspected the air cleaner and found it to be very dirty. I removed it, cleaned out the housing and replaced the filter with a new one. The car has run smooth ever since. I have three engine codes they are as follows:

1. P0302- Cylinder misfire detected in cylinder #2.

Would the codes caused from the dirty air cleaner still be there, or would it have reset itself?

2. P0400- EGR System fault. ECM has detected too little flow on the EGR system.

3. P0170- Fuel Trim Bank 1. The computer has recognized a rich or lean condition on one engine bank only.

I picked up spark plugs, oil and oil filter, fuel filter, a bottle of injector cleaner, and carb cleaner (to inspect for vacuumleaks).What is the correctway to test the oxygen sensor?

Now I havea lot of experience working on cars, but I collect classic muscle cars. I have no idea what a EGR or Fuel Trim Bank are. ANY help would be greatly appreciated! Any pictures, diagrams, mental telepathy, ANYTHING would be greatly appreciated!
Thanks!

Sal rd62rdstr1@aol.com (520) 419-8683

 

Clean the mass air sensor with crc brand maf cleaner.replace the o2 sensors they are 100000 mile maint items.clean or replace the egr valve and clean the egr tube it is blocked by carbon.Get a plug tester and check plug 2.
parts www.autohausaz.com
ohlord
exhaust gas recirculation
fuel trim is the + and - varients that the maf and the ecu trigger to maintain the perfect so called air/fuel ratio for best combustion.
never ignore a cel for a year if the systems affected are the right ones it will eat a cat and then you have the cat converter to replace for big money.

 

I replaced the spark plugs yesterday. Pretty straight forward. I visually inspected the injectors, paying special attention to the #2 position. I didnt notice anything out of place. I ran into a problem trying to changethe oil. I cant seem to get any type of filter tool on the filter. Is there a special tool for this? Any tricks?

Should the codes reset themselves or do I have to have them reset?

 

If the condition that caused the codes is gone they will clear after 3 drive cycles that the condition does not repeat.You never have to have any shop read or reset the codes if you have the #94169 od2 scanner from harborfreight tools for $39 online or at the hb near you if you take the internet ad they will meet their online price
ohlord

 

M104 engine has a special oil wrench although a lot of members with that engine just pick up a 6piece set of filter wrenches at walmart,one of them is the proper size.
ohlord

 

ohlord has answered most of your questions.

Although codes will clear by themselves after a number of drive cycles if the fault has been rectified, it is best to do a rescan to see what codes remain / have reappeared.

The misfire on No. 2 may be pointing to a coil / lead issue or other more significant issues. However the fault may have disappeared with the plug change / MAF clean.

Not sure if you can swap leads about on M104 unlike on M112. Changing component position is a useful way of seeing if you can move a problem from one cylinder to another without buying new (expensive) parts. Of course if the problem moves you need a new part.