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Hi guys, Last night the yellow engine light came on. This morning I connected up my ICARSOFT MB11 and checked. Found two CURRENT and 2 HISTORIC codes. The two current codes were P2767 and P2768 and stated "Secondary Air Injection at Right and Left Bank of Cylinders ( function chain )". Now that is all well and good but I don't compute! What does this mean?
The two Historic were interesting : They were P0410 and stated that Y3/8N2 ( Internal Speed Sensor) (VGS) is not available and then signal from this speed sensor " not available". This is very interesting in that I experienced the dreaded auto box Control Panel "needs replacing" diagnosis from both MB and Indy some time ago. I was far away from affording +/- R50 000 for a control plate replacement so I did a thorough clean up in the box and replaced all the oil. Since then I have a smooth and efficient gearbox and no current problem with that sensor - HOW DOES AN OIL CHANGE RENEW THE SIGNAL FROM A SPEED SENSOR ?
Anybody out there that can inform me what the 2767 and 2768 mean in a way an ordinary mech can understand, I will be most greatfull.
Thanks
Drive safe all
 

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Reading from my notes I got the codes mixed up : p2767 and p2768 were Historic and p0410 was the current codes refering to "Secondary Air Injection at right and left bank of Cylinders". That's what I need translating please.
 

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Secondary air injection refers to the air pump circuit that is used in a cold start for emissions purposes. Likely your pump or relay has failed.

The speed sensor gets weaker over time cleaning the surface can get you a bit of time as it make the conditions more ideal but this error will come back.
 

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Regarding P0410 - do you hear the air pump motor running for the first minute during a cold start?


There is a relay that controls this motor, and it can burn out. If you don't catch it early, it can also cause excessive heat in the Front SAM and melt things in the SAM underneath the relay.


There is also a vacuum-controlled valve that must open when the pump is running, if this valve is not working it can also cause this code.
 

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Thanks very much guys. The pump appears to work fine so I'll have a look at the Vac valve and see if she is OK. If that is OK I'll then check the O2 leads at the Cat together with the connectors, I presume if there is a problem with these it would also signal P04010. Will let you know how it goes. Many thanks again.
Drive Safe all
 

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The secondary air injection is activated by the ECU for about a minute upon cold start in order to reduce tailpipe emissions. However, the secondary air injection is also activated at other times as well by the ECU - after the engine is hot - for purposes of testing the pump and valve. It is these tests that set the P0410 code. During testing, the ECU looks for signature changes at the 02 sensor that confirm both are working. If it doesn't see the signature, it sets the code. The upshot is this: if you have even a slight suspicion of problems with your 02 sensors, you should resolve those first before repairing your pump or valve.
 

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. . . if you have even a slight suspicion of problems with your 02 sensors . . .
Mileage should be one of your suspicions. O2 sensors are designed for a life of 75,000 - 100,000 miles. By that point they are starting to get lazy and less responsive.
 

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Discussion Starter #12
I am at 123 000 klm so just about "in the slot" so to speak. I will bear that in mind, thanks a mil.
Safe driving all.
 

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Seems to me that just about everything is giving in between 100 000 and 140 000 klm. They don't seem to make the Benz as good as they used to ??? Glad I got a low mileage car.......Just means that I am the one to "renew" the parts. Ha Ha
 

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The two Historic were interesting : They were P0410 and stated that Y3/8N2 ( Internal Speed Sensor) (VGS) is not available and then signal from this speed sensor " not available". This is very interesting in that I experienced the dreaded auto box Control Panel "needs replacing" diagnosis from both MB and Indy some time ago.
Drive safe all
If you already had this confirmed by the MB ( who clear the codes ) then you might need a conductor plate soon.
The fault is intermittent and at the beginning will be stored in ecu and not current.
 

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Many thanks i860, I got the codes mixed up - the speed sensor "Historic" codes were P2767 and P2768 ( not P0410). I did get the diagnosis from MB but they didn't clear any codes, didn't even attach their system to the car, just relied on my readout. Think you are right that I will be going down that road sometime but hope that it is not before the results of the work MARVIN is undertaking, might be able to save some time/money. We'll see.
Safe driving all.
 

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Many thanks i860, I got the codes mixed up - the speed sensor "Historic" codes were P2767 and P2768 ( not P0410). I did get the diagnosis from MB but they didn't clear any codes, didn't even attach their system to the car, just relied on my readout. Think you are right that I will be going down that road sometime but hope that it is not before the results of the work MARVIN is undertaking, might be able to save some time/money. We'll see.
Safe driving all.
Mine will be installed in a few days. I'm waiting for the plate and the oil to show (should be soon) and then I have to arrange the SCN coding.

It ain't the sensors bud. It's probably more likely the ribbon cable or the TCU. Either way, it's likely you will have to order up a conductor plate :(

Remember, if the sensors were 'weak' than resetting the TCU would not fix them. Also, there's a few shop owners in Europe that tried both installing new sensors and having one of the aftermarket 'reman' conductor plates with new sensors - in both cases they came back :(

My bet is on the ribbon cable but without knowing what Mercedes does during the reman process we will never know 100%. You can sure though that when my OE reman arrives I will be examining it pretty closely before installing!
 

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My OE Mercedes reman conductor plate came in today :smile:

Close examination shows that the TCU is new. Date on it is August 20 2018. Ribbon cable is new. As far as I can see, it looks like the plastic carrier is new as well. TCU has a big #3 on it, old one has #2 Both are NAG2

Old one is VGS2-NAG2
New one is VGS3-NAG2

I'm thinking that is a revision, ie, series 3 so probably major revision.

I don't have the old one out yet so I can't directly compare them but the TCU & Ribbon Cable are new. I would assume sensors were replaced as well. Makes me wonder what is old as they are called reman units from Mercedes.

It came with tranny pan bolts, conductor plate bolts and that tube that goes up to the trans (not the fill tube).

Sometime next week the service kit should be in so timing for the job will likely be next week. I am very curious how black the fluid will look since it's only been in there for probably less then 10,000 km's. My guess is that it will be burnt due to slippage.

I was originally thinking of replacing the entire trans with an OE Mercedes reman as the price was originally supposed to be $5,600 but when I met with the partsman he thought they did not come with the valve body or conductor plate - add $3,000. It totaled $10,000 for parts plus my installation etc.

I got the conductor plate for $1,000 and $250 for the service kit. My thinking is if the trans has been damaged excessively (clutch slip) then I will rebuild it myself. I checked the cost on parts and tranny kit with steels, frictions & pistons is less then $1,000. So it's a no-brainer in that respect.

Can't wait to get at it. Especially since once my Xentry tool shows up I can re-adapt the trans etc and make it like it's supposed to be.

When I do the job I will again separate the valve body and clean it as well as ultrasonically clean the solenoids. In short, I will make it like new again. We will see just how much contamination has re-appeared in the last 10k.....
 

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Now you just need to install it and:
- Program control unit.
- Perform SCN coding.
- Learning to the drive authorization system
- Teach-in of selection range sensor
Tx i860 !

It sounds like I should wait until my pass-through unit comes in (probably next week). I'm going to get someone to come over and do the SCN coding for me. I want to make it as easy/fast as possible. Should I back up my old TCU with my pass-through tool before doing the work?

Will the person doing the SCN coding need it?
 
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