1998 C230 Benz 2ndary Air Injection System Problem

[Moylan]

Would anyone happen to know how to access & replace a variable resonance flap for a 1998 Benz C230? Engine check light lit up & diagnostic reader showed "PO140 Secondary Air Injection System Malfunction." I understand this means that the switchover flap bearing is worn out & the above part must be replaced. Any ideas on price for this part?

[mercedessd]

Would anyone happen to know how to access & replace a variable resonance flap for a 1998 Benz C230? Engine check light lit up & diagnostic reader showed "PO140 Secondary Air Injection System Malfunction." I understand this means that the switchover flap bearing is worn out & the above part must be replaced. Any ideas on price for this part?


who told you this code refers to the flap?? 9 times out of 10 it is a defective oxygen sensor, what happens is during the self test for obdII the air pump will come on, and if the o2 sensor does not drop to a specified voltage it will thow the check engine light and set code P0140,
i have also seen plugged air injection ports cause this which will require removing the cylinder head to clean.
but remeber nothing beats the proper diagnosis by a competent shop with the proper factory tools.
this check will require activating the air injection circuit while watching the o2 senso reaction time. for it to pass it need so be less than 40MV withion 60 seconds. usually it should drom down to the 20's in that time

[Moylan]

Thanks for reply. Symptom before engine light lit was a loud "whirring" noise from the engine compartment, which the factory repair CD indicated was a precursor to the above part needing replacement.

[mercedessd]

Thanks for reply. Symptom before engine light lit was a loud "whirring" noise from the engine compartment, which the factory repair CD indicated was a precursor to the above part needing replacement.


check the hoses at the pump and plumbing, maybe a hose has fallen off or split

[Moylan]

Would you happen to know where the pump is located? Thank you.

[mercedessd]

Would you happen to know where the pump is located? Thank you.

passenger side below the alternator, round black unit, on this model it is electric