[bobehill]

Just got the car back from my daughter in limp mode; quoted $2500 at a couple of shops, but replaced the shifter for $200 and it shifts perfectly, didn't even have to clear the computer, it just automagically worked.

Car runs great but shows CEL with P0105 Manifold Absolute Pressure/Barometric Pressure Circuit Malfunction and P0400 Exhaust Gas Recirculation Flow Malfunction. I'm guessing these are both smog devices, but I'll eventually have to pass smog, and would like to clear the problems on general principles.

Are these problems likely related, or are they just bad luck? If anyone can suggest what the cheapest way to proceed I would appreciate it. I hesitate to do the amateur approach of throwing electrical parts at a problem, although it's generally cheaper than paying a shop to throw electrical parts at the problem. If these parts can be cleaned or salvaged and tested I'll give it a try. If anybody has a 'how to' or some pictures that would be great.

I don't see any loose vacuum lines under the hood, but I don't know what the MAP sensor and EGR device look like, or where they are located. I've seen some pictures of the C230 parts but not the V6; I'm guessing the V6's are all pretty similar.

Thanks for your patience,
Bob Hill

 

[Deplore]

Both problem are likely a broken/cracked vacuum hose. Common problem.

Map sensor, EGR is on the back left side of the engine if viewing from this angle (in the pic). Take off the air intake, and you will see EGR valve. It too has a vacuum line going from intake manifold to the solenoid.

 

[bobehill]

Both problem are likely a broken/cracked vacuum hose. Common problem.

View attachment 2804070

Map sensor, EGR is on the back left side of the engine if viewing from this angle (in the pic). Take off the air intake, and you will see EGR valve. It too has a vacuum line going from intake manifold to the solenoid.

Thanks! And are the EGR Valves the round silver things on either side of the picture with vacuum lines attached? So far I haven't found any obviously damaged vacuum lines, but from everything I've read, the vacuum leak is the most likely culprit for both error codes. So perhaps I should just get a bunch of new tubing and redo all of it - pretty cheap option to try.

 

[Deplore]

And are the EGR Valves the round silver things on either side of the picture with vacuum lines attached?

No. Please read carefully.

Map sensor, EGR is on the back left side of the engine if viewing from this angle (in the pic). Take off the air intake, and you will see EGR valve. It too has a vacuum line going from intake manifold to the solenoid.

Also try to google a picture of M112 EGR valve. You will see it.

 

[Witek_M]

Thanks! And are the EGR Valves the round silver things on either side of the picture with vacuum lines attached? So far I haven't found any obviously damaged vacuum lines, but from everything I've read, the vacuum leak is the most likely culprit for both error codes. So perhaps I should just get a bunch of new tubing and redo all of it - pretty cheap option to try.

Here is layout of some components on M112 engine. EGR test is dependent on MAP sensor. Remove SAI pump. There are two ports on intake manifold. One for MAP sensor, other for SAI switchover valve. Replace both hoses.

 

[bobehill]

Thanks for the pictures. I'll go take it apart tomorrow and see what I find