eric_in_sd

It's just a laugh a minute with this thing. Check Engine Light comes on, and it's the Bank 1 Cataclysmic Perverter "Catalyst System Efficiency Below Threshold (Bank 1)". Possibly a fluke, as I've never seen this before, and the engine had just barely warmed up, but ... others say the catalytic converters (on a different model) just don't last (https://mbworld.org/forums/c-class-w...ml#post4906075)

Recently changed air filters and plugs. The old plugs looked clean and clear.



Anybody with experience on the GL450's cats?

P.S. You gotta love a car that motivated me to buy my own OBDII reader.

alx

Not uncommon for a 2007. And those cats are expensive.

eric_in_sd

Bah. 111K miles.

Is it a DIY? I haven't crawled under the car to see if it's bolted in or welded.

If the O2 sensors were going, it would throw different codes, right?

Are aftermarket or used cat converters available? I only need this thing to last another couple of years or so.

Thanks for the info, Alx.

eric_in_sd

Followup:

I'm in California, and CARB is terribly strict about catalytic converters. I found that in the other 49 states, you can get "recertified" (aka used but tested) catalytic converters.

I toyed with the idea of taking the car to someplace outside California, but the cost of getting the car there and back would outweigh the cost of new.

I'm going to try some "emissions pass" fuel additives and see what happens. It's hard for me to believe the cat is actually toast, because last smog, 18 months ago, had really good numbers.

I reset the OBDII message and it hasn't come back on.

eric_in_sd

Still didn't replace the oxygen sensors, and the P0420 error has not recurred a third time, after running "Guaranteed to Pass".

It passed smog (California), so I have at least a two year reprieve.

I switched back to 0W40 oil, and the burn rate has suddenly declined. Last time I got 1,800 miles per quart. So maybe it was a bit of oil fouling on the oxy sensor and/or the cat.

noud

Whats up, mate? How is your OBD scanner?

I still have my P0420 coming on every 3000 miles, and then stays for 2 days and off again. I am using this seafoam techron things hopping it will clean something.

But I cant even find cat for sale in Cali, not even online. it looks like only dealer carry them.


Let me know if you will manage to take cat off to see how combs look

eric_in_sd

I got the Veepeak module and leave it plugged in. It works great.

I seem to be holding okay on the P0420 errors, so I'm not doing anything for the time being. I'll probably change the oxy sensor first. Changing the cats is near impossible. Maybe someone could cut them out.

Did you ever change your oxy sensor?

Your only real concern is passing smog, right? I'd put cataclean / seafoam / guaranteed to pass in just before going in to smog. You might be able to take a road trip to Arizona and have a shop install a recertified cat there. Me, I'm just going to hang on, fix whatever I can on the cheap, and if the thing won't pass smog, sell it out of state.

ALKEMIST187

What did you end up doing? I went to autozone, they said the cat is bad, I was wondering whether I should change the o2 sensors first? I got a deal on used, all 4, was thinking of just buying those & putting them in, & praying that the cat was good. What was your experience? Thanks in advance

Bimmer777

This should solve the problem.

http://www.ebay.com/itm/SDT-Oxygen-S...FWL26n&vxp=mtr

ALKEMIST187

It can't be changed with the same socket I used to change the ones out in my escalade? Ive never done it on the benz, that why I'm asking

Bimmer777

I was under the impression all O2 sensors had the same thread, just different length wires. So these things should be universal.

Full disclosure - I havent done it on the Benz either. Have done it on another car in the past a while ago.

eric_in_sd

Universal oxy sensors are cheap - like $45 each. You just have to use their special crimp connectors. Apparently the sensor needs the tiny amount of air that bleeds in along the wire, so if you solder and heat shrink the connections, it will fail. If you're uncomfortable doing the wire connections yourself, pay an extra $100 or so per sensor and it will come with plugs compatible with the MB wiring harness.

Everything I have heard is that when you get a 420 error it is likely the cat itself. However, changing the downstream O2 sensors seems like a sensible thing to try, considering they are pretty cheap - about $50 each.

I have not removed mine, as the error has not returned after two occurrences. I just passed smog, so I have a couple more years of breathing room.

I tried to remove my one (driver side) sensor, and couldn't get it unstuck. But this was with trying nothing extraordinary. I'm still going to try to do it, though. First step will be to soak it with PB Blaster; second step will be to heat where the sensor mounts in the cat; third step will be to heat where it mounts and cool the sensor with freeze spray. As soon as I successfully get it removed, I'll post the results.

The downstream sensors don't look too hard to remove, especially the driver's side. The upstream sensors are buried so far up besides the engine that I don't see how to remove them without pulling the engine.

Changing the cats looks like it involves pulling the engine. I don't even want to think about the $thousands that will involve.

The P0420 error cracks me up. It's telling you to forget about it, sit back, light up a bowl, and 420 yourself into not caring.