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2016 S550 designo Magno Cashmere White (Matte Finish)
2016 S550 not passing smog
Hey guys can anyone help me out? I have a 2016 S550 that has can't pass the smog test. The motor was replaced due to fletcher jones mb messing up my car and also has a tune from oetuning. Any ideas?
From what it looks like, you need to drive your car for an extended period of time in order for the ECU to provide enough information to pass the OBDII scan. I think the minimum is 30 miles after a OBD code reset but I could be mistaken. You didn't fail any of the tests so I don't see that you need any components replaced. But maybe I'm missing something. I suggest driving for 50 miles and trying again. But I'm surprised they didn't tell you that at the emission station.
Hey guys can anyone help me out? I have a 2016 S550 that has can't pass the smog test. The motor was replaced due to fletcher jones mb messing up my car and also has a tune from oetuning. Any ideas?
The same happened to my 05 SL500 2 years ago, although with original engine and no ECU tune. (The first smog check followed the car being inactive for several months waiting for an ABC pump during the Covid logistics shutdown period.) I drove it quite a few miles just prior to the smog test but had the same message as yours. I drove it around town for a few more days and went back at which time it passed with no more problems. So perhaps several shorter trips might help it. Good luck!
For ‘Rediness’ to happen it needs to see X amount of time at Y% of throttle. There has to be a certain number of cycles from cold to fully warmed up. Evaporative Emissions needs to pass one or more tests the car does. It is quite a list. Short answer... number of trips of varying lengths from stone cold that include every imaginable scenario.
I prefer a code.... but once codes are cleared it has to go through rediness again.
For ‘Rediness’ to happen it needs to see X amount of time at Y% of throttle. There has to be a certain number of cycles from cold to fully warmed up. Evaporative Emissions needs to pass one or more tests the car does. It is quite a list. Short answer... number of trips of varying lengths from stone cold that include every imaginable scenario.
I prefer a code.... but once codes are cleared it has to go through rediness again.
Originally Posted by Cosm
no I don't have access to any tools to do so unfortunately
You need more cycles in order to pass. I can't speak to why your car takes so long to acquire, store, and process the data in order to pass it on to the OBDII port, but that looks like what's happening. How long and how many miles has it been since the motor was replaced, and same for the tune? Also, how many fully cold to driven to optimal temperature cycles have you had since both events? I had a car fail emissions tests after replacing a head gasket, but this was on a 1992 Supra way back in the early 2000's. It took me about a week of daily driving to get enough data to pass the test. The tech on my 2nd attempt is the one who told me why it wasn't passing.
2016 S550 designo Magno Cashmere White (Matte Finish)
I've been driving the car for 2 months since the engine replacement, does the codes need to be cleared before it will reset? otherwise driving it will not clear them?
My experience with tunes and smog checks has been once they see a vehicle has a tune, which they can, they will decline to test it and not proceed any further. Heck the dealers of the various auto manufacturers can see if a vehicle has a tune, even if you think you’re being cute and flash it back to stock for warrantee work etc
That scenario wasn’t with my S class, and I don’t know if it pertains to your situation, but I suspect the tune has something to do with it. Maybe the tuner turned off 02 sensor inputs or something to trick the computer as to not give a CEL/throw a code, and that’s why it’s showing not ready to test. Especially since it’s been driven a lot and should be ready.
Bench tune or you have the handheld unit? If you have the handheld unit, load the stock file back on, drive around for a few cycles and hopefully it'll clear up your issue. I'm not 100% familiar with CA smog but based on what I know, any ecu tune non-carb compliant is an automatic fail.
Gotta take the OETUNING tune out, same boat for me but I have the My Genius hand held.
Update, the OETUNING Tune prevents the Star smog check from seeing some of the readyness checks, so driving as suggested will NOT help you pass.
As I said, the tune has to come out. Mine was erased by the MB campaign ECU re write for free. Didn't go back to OETUNING as their customer service is now none existent.Went with Weistec who's tune is CARB leagal and customer service is EXCELLENT! LOVE THE TUNE TOO!
Last edited by Bigg Willi; Dec 29, 2024 at 01:50 AM.
The official process you need to run through is a bit difficult in dense urban areas, or places where there's heavy traffic. The official drive cycle needs to run through a long sequence - https://mbworld.org/forums/m-class-w...dii-ready.html
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