fredersr

For the past six months the engine check light keep coming on on a monthly basis. Innitially I just disconnected the battery and it would stay away for a few weeks. Lately in comes on more often and usually when I'm driving very slow(+/-60kmh).
The Bosch diagnosis showed Fault 003 Secondary Air system Error detected.
Technician did not want to print out what to check for on the program and told me the reset should sort it out. Guess what? The light is back on.
Anybody know where I can start with fault finding. I know It's difficult looking for a intermitent problem.
If I can get the Bosch screen print on relays to check, then it can give me a starting point.
Anybody had simmilar problems with their C32?
Thanks
Shawn

timh718

change the secondary air injection relay first,
if it's still thorw a CODE, changet the secondary air injection pump aswell..
it's a common problem.

fredersr

Where is the secondary air injection relay and the secondary air injection pump on the car?

OLDSCHOOLRICE

There might still be a campaign open on your car for this condition. Stop by your local dealer and have them run the V.M.I. on your car and see if there are any open campaigns. If the secondary air injection campaign is still open you can have this fixed under warranty, regardless of your mileage or year.

c32 dan

it happened to me when i had my car for only one weekluckily i got it replaced by the warranty..been told that if it wasnt for the warrenty it be around 500pound inc labour for the airpump=$1000 usd

1qikctr

its about 800ish with labor. got my replace at 60k miles. going 62k soon.

fredersr

Changed the relay two weeks back but the check engine light is back on. Called Mercedes to get a price on a new secondary pump. They quote me R10415,39 which is about $1388.
Is there a way to test the secondary air pump at home. I don't want to buy such an expensive component, only to find out my current one is still working.
Is there anything else that I can check?
What is the function of the secondary air pump?
Thanks
Shawn

pshek

You can test the secondary air injection pump with a simple electrical tester. Just hook up one end to ground and the positive end between the electrical tester and the positive battery terminal. The pump turns on in the morning and you should be able to hear it. It sounds like an inflatable air bed pump or vacuum cleaner. You should be able to hear even inside the car. It increases the amount of air going into the engine to adjust the air/fuel mixture at start-up to reduce emissions. It looks like a black pump about the size of a canteloupe.

If you look at the picture of my engine in my sig, the pump would be at the bottom left corner of the picture, at least in a W203. The pump is located in a different place on a SLK32.

gaz

I replaced the relay and the pump on my car some time ago for this fault, but about once a month the cel would come on again. Finally found the problem in a loom connector within the front relay/fuse compartment. The wiring to the air pump is just looped within the box. There is a clear(ish) plug connector which has a red wire which had melted slightly causing an intermittant bad connection. I am assuming that LHD cars are similar to my RHD...

fredersr

Will check this out on the weekend. Thanks for the responses so far. Will take my tester hom and test the pump as well. Just hope my pump is not busted. Maybe It's time to upgrade to a C55.