I'm getting a bunch of malfunction codes and am wondering if anyone has had a similiar problem and if so what the fix may have been. I was seeing an occasional CEL but it would alway go out eventually. But then I noticed I seemed to be using more gas and I went hmmmmm.
1. PO176- Fuel composition sensor circuit malfunction
2. PO175- System too rich (Bank 2)
3. PO0304, 305 & 306- Cylinder 4,5, and 6 misfire
4. PO150- O2 sensor circuit malfunction (bank 2 sensor 1, open circuit before cat)
#4 I'm clear on the O2 sensor ahead of the cat but which side is bank 2?
#1 don't have a clue
#2 ok, how do we fix that?
#3 I'm thinin' the fuel mix is causing this. 4,5, and 6 aren't all on the same side, are they?
The car has 19K miles on it so I'm a bit miffed that this is goin on but what the heck. Anybody got any ideas? I'm thinking the MAF could be causing the snow ball to roll down hill maybe? Mr. Wizard, I'm mean Marcus, are you out there?
I'm getting a bunch of malfunction codes and am wondering if anyone has had a similiar problem and if so what the fix may have been. I was seeing an occasional CEL but it would alway go out eventually. But then I noticed I seemed to be using more gas and I went hmmmmm.
1. PO176- Fuel composition sensor circuit malfunction
2. PO175- System too rich (Bank 2)
3. PO0304, 305 & 306- Cylinder 4,5, and 6 misfire
4. PO150- O2 sensor circuit malfunction (bank 2 sensor 1, open circuit before cat)
#4 I'm clear on the O2 sensor ahead of the cat but which side is bank 2?
#1 don't have a clue
#2 ok, how do we fix that?
#3 I'm thinin' the fuel mix is causing this. 4,5, and 6 aren't all on the same side, are they?
The car has 19K miles on it so I'm a bit miffed that this is goin on but what the heck. Anybody got any ideas? I'm thinking the MAF could be causing the snow ball to roll down hill maybe? Mr. Wizard, I'm mean Marcus, are you out there?
Hey, DL. Weird, I thought the fuel composition sensor was related to flex-fuel vehicles. I wonder if it's just a transient code because of what else is going on? Perhaps MarcusF can shed some light here.
Bank 2 is the driver's side (at least outside of the UK ). If you go over to the W210 forum I posted a pdf in the engine sticky (about the CPS mostly) but it has a pic of the O2 sensor you're coding on. Tighter confines under your hood, but the same sensor and same location.
And yep, 4, 5 and 6 are on the same side, which coincidentally is bank 2 (front to back). I'm wondering if the O2 sensor has puked and that's causing fuel delivery problems, triggering the rich code and the misfire codes and the transient composition sensor code.
While a MAF could cause that, it has several codes that are usually suspect for it, too, so while you might try cleaning it (another DIY in the 210 section) I doubt it's the cause of the issues.
How long have you had the intermittent CEL? If you've had misfires and rich conditions on the left bank for quite some time, you might also have a partially plugged cat (or two), which could also account for misfires, poor driveabilty and loss of fuel economy.
The O2 sensor, though, is easy enough to replace. 45NM torque, use a special socket, anti-seize just on the threads (be sure not to get any on the sensor itsefl) and buy it from a known source such as autohausaz.com. It's a bit pricey, but change it out and clear the codes, dump in a can of seafoam (best price I've seen on it is at Walmart) and cross your fingers.
Take care and enjoy the ride,
Greg
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It sure sounds like the MAF to me.....try that before doing all the other repairs. I had the same O2 sensor etc...codes. When I replaced the MAF (15 minutes), they all went away. I did the clean a few times with short time results. When I replaced it, I have not had an issue since.
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Last edited by tomtomtomtom : 09-17-2008 at 06:03 AM.
I've had the intermittent CEL for about three weeks and it finally stayed on for two consecutive days so I got it checked. A plugged cat? Don't think so with less than 20K miles but I suppose it is possible. The sensor you are referring to is in the engine compartment?
gregs. tried to do a search and couldn't come up with your PDF. Can you post a link please?
It sure sounds like the MAF to me.....try that before doing all the other repairs. I had the same O2 sensor etc...codes. When I replaced the MAF (15 minutes), they all went away. I did the clean a few times with short time results. When I replaced it, I have not had an issue since.
Quote:
Originally Posted by dlbehrns
I've had the intermittent CEL for about three weeks and it finally stayed on for two consecutive days so I got it checked. A plugged cat? Don't think so with less than 20K miles but I suppose it is possible. The sensor you are referring to is in the engine compartment?
gregs. tried to do a search and couldn't come up with your PDF. Can you post a link please?
Hey, DL. The only way it would be a plugged cat would be if you were running rich enough to plug it for long enough. I doubt three weeks would be enough unless you were really driving it hard during that time.
The fact that tomtom had the same O2 code and it was his MAF I guess would make me reconsider that possibility, but to have the O2 code and the misfires on the same bank and no MAF code, I think I'd still first replace the O2 sensor. Speaking of which, here is the link: http://www.benzworld.org/forums/w210...ensor-pre.html (It's listed under CPS because that was the point of the post, but one of the pics in the PDF shows the Bank 2 O2 front sensor really well.)
I also posted a Bosch spec sheet for testing the MAF, basically uses a vom and air to blow over the sensor once you remove it. It is here: http://www.benzworld.org/forums/w210...m-amm-mas.html So you could run this test to see if your MAF is within specs, if so you're almost certain it's the O2 sensor.
All of that said, it's probably also worth simply inspecting the O2 sensor and wiring over there. You might have a rat that gnawed on it or something, the connector might have some corrosion in it, etc., certainly worth a hard look before getting in deeper.
I think the position of the sensor on the 210 must be different then on the 208. On mine, looking down from the back of the driver's side valve cover, all I can see is the back 1/4 of the exhaust manifold. I can't even see the steering coupler. There is a cowling/firewall that separates the engine from power brake booster etc so perhaps the coupler is under that, but I ain't seeing no Bank 2 pre-cat O2 sensor. Anybody else out there had a similiar 208 issue?
Just had a thought: I was conversing with MarcusF regarding changing out cats and he sent a pic showing the before and after cat sensors so perhaps it is down on exhaust just before the cat and I'm not looking in the right place.
I don’t know what the fuel composition sensor does.
I do know where the O2 sensor is on a 2002 CLK430. The #1 sensor is just before the primary cat. If it’s in a different spot on a CLK320, it can’t have been moved very far. The sensor has to be before the cat, and there’s not a lot of tubing between the head pipe and the cat. If you can’t see the wiring, that may be the first problem – the wire has come off. If so, locate it, plug it back in, and see if the code clears. Wouldn't that be nice.
I've located the sensors before and after the cats from the underside of the car however, unplugging the bank 2 sensor is proving difficult if not impossible because the difficulty of access. I was trying to figure it out on the post sensor on bank 1(passenger side) because they look the same and there's some room to move but I'm not able to get anything to come loose and I don't want to yank of the wires too hard. there is a thin plastic collar at the top of the sensor where the wiring feed into the top of the sensor but it ain't movin'. I can see how the sensor can be removed from the piping with a wrench but that's it. And, all four sensors lead into a four plug cluster on the right side(that probably leads to the ECU)but I can't get anything to come loose there either. I can usually work with something long enough and get it figured out but I'm stumped. Any suggestions?
). If you go over to the W210 forum I posted a pdf in the engine sticky (about the CPS mostly) but it has a pic of the O2 sensor you're coding on. Tighter confines under your hood, but the same sensor and same location. 
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