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Seeing as this is my first post I figure a small introduction on my part is in order:
Im currently 32, I am from The Netherlands and own a shop specialising mostly in general repairs, maintenance, MOT and tyres. I own a W109 300SEL and since last week a 2003 w203 200 kompressor
The w203 was offered as one with work, mainly concerning SRS warning, ESP warning and MIL light on. Also some rust on the known places. Car had not been serviced in quite some time.
I picked it up very cheap, and figured what the hell.
I started off reading all the codes, delete them and see what comes back. I am using a Delphi DS150e for OBD reading.
Anyway after clearing the codes and driving it for a week, I can now see what codes are coming back and thus forming the problems. The MIL light came on very fast btw. I won't get into the ESP and SRS codes at the moment, as its the MIL codes that are giving me a slight headache.
Code that showed was P200B Air mass meter (hot film) btw I have to translate the codes in English as my setting for Delphi are in Dutch, so translation might not be spot on. Car drove reasonably well, however idle was fluctuating slightly. I have no reference as to power, because I bought the car like this.
Without immediately replacing the MAF I figured i´d google the code. Found info but can´t cay I found a definate answer. However many spoke of similar problems and that a dirty throttle body. I figured its a good place to start and went to clean it.
Now here comes my first question:
Everyone speaks of plurar when discussing the throttle body however I soon found 2 under the hood? One on the MAF housing and 1 one the right hand side of the engine (left when infront of car) connected to the air intake with the coolant overflow (or whatever) line going over it.
They are pretty much identical except that the MAF side one has a port for a vacuum line.
Both of these, but especially the MAF sided one were dirty. I took out the butterfly flap and cleanend them good. I also found info on the interweb talking about cleaning the tracks inside the throttle because of carbon buildup. I did this aswell for both and found quite some carbon on the tracks. I used wd40 and soft cloth to clean these.
I furthermore changed the airfilter, cleaned the MAF and the piping of oil residue.
Then I put the key in second position and hear a lot of clicking, faint whining etc from both throtthe bodies. Seems normal to me.
Then I started the car and idle was going all over the place randomly. I first figured there might be some brake cleaner residue in the piping used to clean. However it stays. The car drives but it' doing worse than it does when I bough it.
I checked for codes again:
P200A: Throttle valve potentiometer
P201C: Random/multiple misfires detected
p2006: Air intake temperature sensor
p200B Air mass meter (hot film)
I googled and figured it might be a vacuum leak somewhere, or that the throttle needed to be reset. I reset the ECU by the turning to key 2 position, throttle down 15 secs, key back to 0 and taking foot off throttle. Leave car for couple of minutes. I also took everything off again and redid all clamps and hoses. None were forgotten first time.
I do have to say that when I took off the left hand side throttle the first time, the small vacuum hose connecting to the valve cover broke in 2 peaces, but I am not sure this is what is causing the problems. Its part number A1110182982 btw.
I temporarily taped up the pipe, cleared the codes and started the car again. No difference.
So who can help (and tell me what the second throttle is for)?
Could it be that cleaning the carbon tracks is causing the brushes that touch them aren't contacting right? Or is the cracked pipe crucial? Or anything else? I'm ok in putting money into this car, but I'm not a fan of replacing parts in the hope to find the problem (i.e MAF, throttle housings etc)
Much thanks reading all the way to the end for those that actually did
Ok these two pics show one throttle body on top of the supercharger, just under the plastic resonator for the SC and the other one is under the plastic covers, connected to the MAF. For me, the one on the MAF side is closed in rest position and the one of the SC is in open position during rest.
Can anyone help which of these 2 could be throwing the P200A throttle potentiometer fault?
Also, the M111, like most engines with superchargers, has:
o a Throttle Body near the MAF
and
o a Bypass Valve at the supercharger.
Bypass Valve operation for an M111:
In Normal mode, with the air going through the supercharger:
The bypass valve in an M111 will be closed.
The air will go into the side of the plastic covering, to the back of the plastic covering, into the intake of the supercharger (back near the firewall), and out the exhaust port of the supercharger (front near the radiator).
In Bypass mode:
The bypass valve in an M111 will be open.
The air will go into the side of the plastic covering, through the bypass valve, and out the exhaust port of the supercharger (front near the radiator).
I will try to do the relearn sequence as described in the thread.
However I am confused that you say the bypass valve is closed in rest position, whilst mine, and the one on the pic above you posted is open?
Furthermore, do you or anyone else know if it's possible to reset both the throttle body and bypass valve with Star diagnosis? And seeing as only one of the 2 valves is called a throttle do you recon the fault code (p200a throttle potentiometer) is coming from the throttle body and not the bypass valve?
I will try to do the relearn sequence as described in the thread.
However I am confused that you say the bypass valve is closed in rest position, whilst mine, and the one on the pic above you posted is open?
Furthermore, do you or anyone else know if it's possible to reset both the throttle body and bypass valve with Star diagnosis? And seeing as only one of the 2 valves is called a throttle do you recon the fault code (p200a throttle potentiometer) is coming from the throttle body and not the bypass valve?
STAR/DAS
I'm not that familiar with the STAR/DAS system.
Thankfully, I haven't had the need to use it yet.
Throttle vs Bypass
From what I've read and little I know, I would say that it's the throttle that is giving the error, and not the bypass valve.
Bypass
A bad bypass valve will be shown as an error. Like the throttle, there is a command motor and a position sensor feedback. So, the computer knows when the bypass valve isn't working properly. I don't know what error, or errors, are given for a bad bypass valve.
Bypass Valve Operation:
When the engine is not running, the bypass valve will be in the bypass-supercharger-position.
The PCM/computer will put the bypass valve in the flow-through-the-supercharger-position only after the computer determines that the engine and supercharger are in good/working order.
For example, if the serpentine belt broke, then the supercharger would not be turning. If the bypass valve defaulted to flow-through-the-supercharger-position, then the engine could never start (there would be no air flow past the non-turning supercharger).
There are other engine errors where the computer will bypass the supercharger to try to prevent engine damage. I don't know all of the conditions, since I haven't seen an official chart.
02-24-2017, 02:52 PM
