W203 C230 - P0422, P0432 - sorted now P0410

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ex4x4

New Member
Joined
Oct 21, 2013
Messages
28
Location
County Durham
Car
2006 C230 se - 2004 CLK200k - 2010C180 estate - BMW X5
Hi all - just an update ( albeit long winded) regarding my P0422,32 faults, on my 2006 c230 w203 with M272
This fault generally includes post cat O2 sensors but fault still remained after swapping them out the fault still occurred.
Against common sense - I then swapped out the pre cat O2 sensors (with Bosch, but not oem) - thinking they had been in for 100k and maybe becoming a bit lazy in reaction to fuel /air trims triggering the afore mentions codes.
( on a side note - you CAN solder these joints without the world ending, although you do need a high power iron to get solder to "wet" the conductors)
SUCCESS - although short lived.
The codes have dissappeared - only to be replaced with the annoying P0410 secondary air system fault.
I have since systematically worked through and proved out every component of ths system ,but fault ever present.
works completed.......
Air motor - was working although noisey. removed /stripped/cleaned with electrical contact cleaner. bearing degreased and repacked with grease. Rebuilt and refitted - now blows like a tornado.

All vacuum lines tested and holding over 20"hg.

Vacuum control valve - removed, flushed through with contact cleaner and tested - holds vaccum.

Vacuum operated diapragm/check valves - diapragm side checked for leaks - ok. Valve stem lifts around 5"Hg and fully opened at 10"Hg.
valve seat cleaned with carb cleaner. check valve enclosure/reeds were coked up. stripped components ( drilled out reed reatining bolts) and decoked parts. rebuilt. reeds close on reverse ( exhaust side) flow and open on intake ( air pump side )flow.
NB found reeds to be naturally semi open - not sure if they should be normally closed??? but left them in their discovered state.
Whilst diaphragm valves were removed - the manifold ports were tested for free flow with air line - found to be open and clear.

during operation a vaccuum gauge has been attatched to vaccuum in line from vac' control sol' valve to diaphragm valve to see what sort of vaccuum is being generated and for how long. when air pump sequence is initiated - the system pulls over 20" Hg - so Im sure diaphragm valves are fully opening.

I have ran car with Torque app running and monitored O2 sensors during cycle. Now being a wide band 5 wire O2 sensor - I'm unable to measure output in mv but can monitor Lambda equivalent ration both commanded and actual. during cycle the commanded ratio is 2.0 and actual is 1.2.. Thinking this was down to air pump delivery dropping off - I have tried blowing an airline into air pump intake hose at same time in the hope the extra air will increase O2 actual reading but to no avail.


Other possible relevant info - long term fuel trim values around 7% bank 1 and 4 % bank 2 - although short + long trim never above 10% and generally short term in negative %. Maf sensor changed to try to change these figures to no effect. - possible samm amount of umetered air but not a great concern.

So pretty stumped now - not entirely sure what is causing error code.
Any help would be greatly appreciated.
 

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