e320 / Code 4 / So what now?
 

Hi everyone,

My check engine light came on once again. With the key in the on position (car off) I held down the button under the hood for 3-4 seconds. The light then flashed 4 times. I did it again to see if there were any other codes and it flashed 4 times once again. I then cleared the codes by holding the button down for more than 6 seconds.

Code 4 states: Air injection inoperative. So what now? What are the components that may be at fault here?

I should point out that the car runs fine and I recently replaced the air filter.

Thanks,
Michael
95 e320 Wagon / 100K

It's that Bean Town air screwin' up your injection..

First check is to see if the Air Pump runs when you first start a Cold car..

Does it??

Could be the Bean Town air for sure! LOL

How do I know if the air pump is running?

Thanks Arthur!

You have to start the car with the hood open..it is the belt driven pump over by the air-filter ... you can hear it run.. It only runs when the engine is cold at start-up and it only run for a min or so.
It is emmissions device that pumps air into the exhaust just til the cat heats up. Usually when that code comes up, my firsts check [ after I know it is actually coming ON ] is to pull that plastic cover in front of the engine..you will then see a white plastic vac line crossing over to a couple of valves ..that line always cracks and breaks and when it does , the Air Pump valve does not work so that code comes up as #4
I would also look at all those lines in that area seeing thatyou just worked in that space. May just have a vac line off.

Check those out and see if you find anything..

Thanks Arthur! I'll check it out tomorrow and will post back to let everyone know my findings.

Michael

you know what Ihave the same problem I have 95 e320 same code air injection mine doesnt have power going to the pump . I can not find the location of the air relay even I check the diagram something wrong the power goes pin 15 of the ECM such a headache Michell and all data their the same good luck to us hehehehe let me know if you find something...

Check fuse 7