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S600 TT - the dreaded P0410 code (and the fix)

13K views 37 replies 9 participants last post by  cowboyt 
#1 ·
Hi folks,

My '03 S600 was throwing a Check Engine Light. I didn't like seeing that because I prefer to keep my cars in good repair. Additionally, that's an automatic failure during the annual inspection, for those who live in areas where they do that (e. g. California).

I may not live in California anymore, but still, time to do something about this. I don't like broken stuff on my cars.

STAR Diagnostics showed a "current and stored" P0410 code, which refers to the Secondary Air Injection function chain. And what, pray-tell, is this "Secondary Air Injection"? Well, it's a hack that M-B did to try to make their emissions numbers look better when the engine's cold. It's an electric air pump that blows air into the exhaust, right before the catalytic converter, to try to heat up said converter sooner, so that it's more efficient sooner. It sounds just like a Dyson hand dryer, or a hyperactive vacuum cleaner, and it goes on for maybe 30 to 60 seconds. The M-B-specific code for this P0410 fault code is P2003.

STAR Diagnostics also showed codes P0443, P0444, and P0445 as a combined stored code. The M-B-specific code for that is P2026.

Clearing the Check Engine Light would work for maybe 20-50 miles. Then, it would come right back on, all nice 'n' yellow-orange. So, obviously this is a current problem that needs to be fixed.

I tried activating the pump via STAR. Yep, it came on, with that nice, loud whine. Dyson, beware! :) So, clearly, the Secondary Air Pump was fine. Good thing, too, 'cause that thing's EXPENSIVE.

So, I next tried activating the Purge Control Valve from within STAR (this is component Y58/1 in the STAR diagram). When activated, it's supposed to click a lot. Sure enough, I could both see and feel it clickin' away like a cricket. Looks like that's working, too.

HOWEVER...I noticed something else as well!

When you activate the Secondary Air Pump, there are a couple of sensor voltages--I'm guessing the oxygen sensors--that were hanging around 700 to 800 millivolts (mv). They're supposed to go down to below 40 mv within 60 seconds. Well, THEY WEREN'T!! They were alternating between 93 mv and close to 800 mv, each one of 'em. That's not supposed to happen when this air pump is on. Since the pump's working just fine, then clearly either there's something wrong with *both* sensors...or perhaps there's something wrong with the Purge Control Valve that's supposed to activate when you turn on the Secondary Air Pump. Sure, it's a-clickin' like it's supposed to...but is it really working? Or is there a fault inside of it?

So, figuring one component will go out faster than two, I installed a new Purge Control Valve into this V-12 and tried STAR again. The part cost me $70 online, shipped.

LIKE MAGIC IT WAS....

The voltages are now reading 9 to 10 mv, both sensors, when the Secondary Air Pump gets activated. Turn it off, and it goes right back to 700 to 800 mv. The Check Engine Light does not turn on anymore. And I'm now being more enviro-greenie! :)

I'd post the pics that I took, but my phone doesn't want to cooperate. If I can get it to cooperate, I will post the relevant pics.

The moral:

STAR Diagnostics is a Very Good Thing. It can usually tell you exactly what's wrong. If it can't do that, like in this case, it can point you in the right direction with a little bit of thought on your part. Who knows how much this would've cost me at even an independent shop, let alone the dealership?

When you wish upon a STAR...
Saving money, yes you are...!


.
 
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#3 ·
Someone bumped this thread to post a helpful YouTube video, and that helped jog my memory about getting the photos off of my cell phone. Turns out it was a bad cable causing the problems back then, not the phone. Here are the pics, for those who may run into this later.

In pictures IMG_1232.jpg and IMG_1233.jpg, you'll see the fluctuations of the sensors going between about 700 mv and about 94 mv. They shouldn't do that.

In photos IMG_1207 and IMG_1208, we see SDS giving us an idea where the problem likely is. It's not pinpointing it for sure in this case; a little bit of troubleshooting was in order. But SDS does get you in the ballpark so that you can troubleshoot it more easily.
 

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#4 · (Edited)
And here's what it should look like when things are working properly.

Pic IMG_1253.jpg shows us what the test looks like in SDS. I managed to catch it mid-fluctuation, before replacing the Purge Control Valve. At this point, the right O2 sensor was fluctuating down, while the left O2 sensor was on its way up.
Pic IMG_1254.jpg shows us the end of the voltage swing, as you saw before. Again, this is before replacing the PCV.
Pic IMG_1253.jpg shows us *after* replacing the PCV. Note that when we turn on the Secondary Air Pump, the voltages go waaaay down to 5 and 10 mv. That's what it's supposed to look like, and that's what it *wasn't* doing before, hence the Check Engine Light.
Pic IMG_1253.jpg is just a close-up of the proper readings.
 

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#6 ·
Looks like that code, and the Check Engine Light (CEL), came back this month, i. e. a year and three months later. So, I put the car on SDS. Activated the Secondary Air Pump; that comes on just great. Also ran the PCV valve test shown above. The results aren't quite 5mv and 10mv anymore, more like 26mv (RHS) and 34mv (LHS) after 40 seconds. That's still better than 40mv in 60 sec, though, and thus within what SDS says is the spec. Cleared the codes and started driving again. A couple days later, the code and the CEL came back. But we're still within spec, though, when I run the test.

Any ideas?
 
#7 ·
Hi T,

I'd change the LHS one, probably it is going over spec intermittently and popping the Code as @34 mV it is fairly close to the upper limit :wink

HTH
 
#8 ·
Apparently we've got two current part #'s for these oxygen sensors, and I could use some help here from the brain trust. They are as follows.

001-540-95-17
002-540-01-17

This is over at MBOemParts.com, at this link. Both part #'s are listed as item #16.

https://www.mboemparts.com/v-2003-m...5l-v12-gas/exhaust-system--exhaust-components

Looking at FCPEuro, I found that this Bosch part apparently is an older version of the top one.

https://www.fcpeuro.com/products/mercedes-oxygen-sensor-bosch-oem-16125

Its part # is 001-540-38-17.

I don't necessarily mind an older version of the correct part, as long as it's the correct part. But I would like to make sure I get the correct part. M-B sometimes has the same part (e. g. the front HVAC regulator/resistor in front of the blower fan) listed under different part numbers.

Anyone know which of these is the right one for the oxygen sensor on this car? It is a 2003 S600 TT, bone-stock, with the 5.5L M275 engine.
 
#9 ·
@cowboyt ,

Hi,

CANCEL my above post, I misread your SDS Screens, had my head in a million other things last night, apologies.

It may not be a dying O2 Sensor, don't purchase yet ;)

Fact is it could be that the A/F ratios are off on that bank, causing the 02 to read higher than normal !!

Maybe have a look at Vac Pipes for leaks, EGR Function, Misfire counters, fuel trims etc first ??

HTH,
 
#10 ·
Yep, will do that first. Currently the temperature is -12 Celsius (10 deg. F), so when it gets a bit warmer (1 deg. C. will be sufficient), I'll check every hose that I can find. Thanks!
 
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#11 ·
Hi @cowboyt ,

It's been minus 11c here all day even chilly in the Workshop, the Gas Space Heater has been on / off / on / off all day, fairly eating it's way through the propane bottles :grin
 

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#12 ·
Looks rather picturesque, actually, sort of like post card material. And yep, that's about how it looks here, too. I envy your having a building in which to do this sort of work.

At some point, I will be building a garage. My neighborhood is one of the older (for the United States, that is) ones before garages became a thing. When that happens, I will be doing a lot more car work in the winter.
 
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#13 ·
Hi @cowboyt ,

It is beautiful scenery here and the snow looks lovely :) ...............

Trouble is I had a Twin Wheel Iveco Builders Tipper Truck here Tuesday, totally blocking the Workshop doors, (too big to fit inside Workshop), Rear Discs, Calipers, Pads etc etc, which were mounted behind the Rear Hubs, so needing Halfshafts removed, then undo the stoopidly tight 65mm Hub Nuts and get the Hubs off before replacing the Brakes ................

Yep, 6" of snow Tuesday, I was absolutely soaked and frozen by the time I finished the horrible thing :(

Did I ever mention I HATE TRUX :(
 
#14 ·
"It is beautiful scenery here and the snow looks lovely...."

Sounds almost romantic.

That's just a little sprinkling - if you like it that much come to my place; we are buried by it, and it's been - 20C and colder almost every night, with daily snowfalls around 10 - 20 cm.

I HATE JANUARY winters (and don't do any work on cars as I have no garage to use - mine is full of junk!).

Had a 2 day thaw with a refreeze, so you can't even shovel it away.

A well......
 
#15 ·
OK, it was 60 deg. F. (about 15 Celsius) yesterday, and mostly sunny, so I tore into the S600 TT and looked at the vacuum lines. They look like they're in good shape, and indeed, I had replaced several of them a year and a half ago. It makes sense that a line somewhere would be slightly leaking, but I'm not sure where else to look.

Currently the air filters are out, and the intercoolers are being hung up by bungee cords so I can replace the tandem (ABC/power steering) pump's fluid reservoir tank, so this is a good time to start looking for things. Anything else I should be looking at?
 
#16 ·
The CEL is coming on more frequently after clearing it. So, I took a look at the readings. After running the Secondary Air Pump for 60 seconds, and you can definitely hear that pump working, the readings never go below 49mv, and they seem to settle at 54mv. That's out of spec; it should be below 40mv. The last time I saw out-of-spec readings like that, the Purge Control Valve had gone bad, almost a year and a half ago.

Therefore, a new Purge Control Valve is on the way, as of tonight. The part # is A-000-470-88-93. Let's see if that fixes things again. If it does, that means something is messing the PCV valve up. Any ideas?
 
#17 ·
Hi @cowboyt ,

Have you tried spraying Carburrettor Cleaner or Starting Fluid all around the Vac Pipes and Manifolds etc with Engine Running ?

When you have a leak and spray that stuff near it you can hear the Engine note change :wink

HTH,
 
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#18 ·
I have not yet tried that; didn't occur to me. Thanks!
 
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#19 ·
Replaced the PCV and cleared the codes. Ran the Secondary Air Pump with SDS. Now it's acting like it was originally in 2017, i. e. the voltages are fluctuating between 90 mv and 800 mv even with the pump on. It's certainly not going down to below 40 mv. This really sucks.

On the way home tonight, the Check Engine Light came on again, close to home. This was after about 25-30 miles of driving, post-PCV-replacement. I actually heard the Secondary Air Pump come on while at a stop light, so I know that the pump itself works.
 
#20 ·
I don't know about the V-12, but on the V-8 engines, one common cause for the P0410 code is that the air passages into the exhaust port areas can get plugged up with carbon.

A couple of years ago, I used a variable-speed drill driving an eighteen-inch piece of square 0.105" string-trimmer cord to roto-root the passages and clear the code on my 2003 S430. For some reason, the port on the driver's side seems more prone to plugging.

Of course, I later simply used SDS to tell the computer to ignore the P0410 code...
 
#21 ·
O2 sensors, especially the upstream ones, are a consumable. If they are original, not a bad idea to replace them just as pm IMHO. Granted it will run you around $200 for a set of Bosch sensors though.

But then again I have seen them last a looooong time too. Parts darts? Maybe. But just a thought.
 
#22 ·
I hate to play the parts lottery...but it may be worth trying out one side. Replacing the PCV valve didn't help.

Before I do that, though, I think I will try looking at the air passages. Maybe they are clogged.
 
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#23 ·
Hi @cowboyt ,

If you remember, my original gut feeling was swap the Lambda (O2 Sensor), but then, changed my mind due to the cost and the possibility of it being an Air leak, or other simple problem ...............

Now however it is down to what is the easiest job to do I guess, (clean out the Air Passages or fit a Lambda (O2 Sensor), and cost, ...................

I pay average of £180 from Mercedes depending which Vehicle, and personally on something as critical as a Lambda, I won't fit any other Brand :wink

HTH,

PS I keep meaning to ask you to send me a link or tell me exactly where are those pix you want editing, I looked at link that you pm'd me but couldn't find the pic links ?????

Apologies for the delay, but work is really double manic here right now ;)
 
#25 ·
Thanks, guys. This weekend is supposedly going to be good for outdoor automotive work, so hopefully I can get to this. Got the fiance's Civic front suspension to finish first, but after that, yep.

And yes, @Triple cranks: you're right, and I, too, use Rock Auto quite frequently. Great site if you know what you're looking for. Matter of fact, that's where I got the aforementioned Civic suspension components. :) Also got the OE Bosch (made in Germany) front HVAC fan from there for the S600, done (I think) late last year.
 
#27 ·
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