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Pete, Mercedes Mechanic
Category: Mercedes
Satisfied Customers: 28219
Experience:  Over 15 years experience as a Mercedes dealer technician
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1996 S320: Mercedes..II trouble codes: P0411..flow..O2 sensor

Customer Question

I have a 1996 S320 Mercedes that is giving me the following OBD-II trouble codes: P0411 - Secondary air injection system incorrect flow; P0141 - O2 sensor heater circuit malfunction Bank 1 Sensor 2; and P1137 - Manufacturer control fuel air metering. What do I need to replace to fix these problems.
Submitted: 6 years ago.
Category: Mercedes
Expert:  Pete replied 6 years ago.
Hello,I will be glad to try and assist you with this,Welcome to Just Answer.


I just need a little more info to assist better.

Did all of these codes set at the same time or were these gradual problems?

Has anything been done or replaced to try and correct these codes?

Let me know so we can continue,Thanks Pete!
Customer: replied 6 years ago.
All of the codes were set at the same time. As of todate, I have not repaired or replaced anything to try and correct the codes.
Customer: replied 6 years ago.
Still waiting for a reply for my question
Expert:  Pete replied 6 years ago.
I apologize for the delay.

If you clear the codes and then drive the vehicle do all of these codes come back?

Let me know,Thanks Pete!
Customer: replied 6 years ago.
Cleared the codes the first time they showed up. After about a week, the service engine light came back on with the same codes.
Expert:  Pete replied 6 years ago.
I would start with checking into both the oxygen sensor codes you have here first as these can sometimes cause a false air pump P0411 code to set.

The other two codes set are both for the oxygen sensor after the catalytic converter.Inspect the wiring to this rear sensor and make sure it is o.k. and there is no corrosion in the connection or connector.

If the wiring is o.k. then this sensor sounds like it has an internal electrical failure and needs replaced.This is most common for these two codes set and may correct the other P0411 air pump code as a faulty oxygen sensor can cause other false codes to set in the computer especially air pump codes.

I have had to replace oxygen sensors before to correct this type of condition here and I suspect this is what you have at fault.

Let me know if you need anything else,click accept if you feel satisfied with your answer as this is how I get credited for my time,Thanks Pete!