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For one, my hope is to find someone who took their car to a dealer and got this diagnosed and would share what they found out.
And Two, I found different things online about what it means:
one google search claims if you ignore this code, you’ll fry the catalytic converter. Other search results said it’s an exhaust leak or bad oxygen sensor. Another google search says it’s a bad power train control module…….
i was under the impression that this forum was to provide answers relevant to the issue. That is why I asked. If by chance I decide to take my car to a dealership for a diagnosis, I will return here and say what was found, however I cannot budget a visit to dealer right now.
So do you know which google search result is the correct answer for code p2099?
the second (post CAT) sensor informs the engine management the (main pre CAT) sensor is managing to do its job correctly - most CAT sensors on cars tend to fail with a heater circuit failure around the 60 to 100k mile mark (often coinciding with 7 to 10 years of life)
peculiarities associated with a load of mumbo jumbo buried in emission control they were told to make difficult for people to circumnavigate, mixed in to designed to fail components and special rip them off software, was never going to be a subject most round the dinner table will have a sensible view on
Dealer wants $300 to diagnose so I was hoping to learn more about what the issue is by posting here first. Seems that somebody must have taken this code to the dealer at some point and I'm hoping they find this post and can chime in on what the problem is. Car runs good and I cleared the code for now to see if it comes back.
Has anything else happened to your car recently that would cause a misfire or a cylinder not firing properly? I know this code rode along with a cam adjuster magnet issue for me. Excess fuel in the exhaust fools the O2 sensors into thinking the Cat is failing. Once I replaced the cam adjuster magnets, I used this stuff called Cataclean. It did a good job and I haven't had that code come back. I'd imagine some good highway miles through the desert might have the same effect though.
No other issues to speak of. I did replace all magnets and cam sensors last year with dealer parts and put some pigtails on both parts to intercept any possible oil in harness if it occurred, also replaced the oxygen sensors and resealed cam covers. The damn thing drives like its in its first mile ever since I did these things. I have to be careful with the gas pedal, don't want whiplash. Funny because I wasn't missing performance before that work so I thought. Only thing different I did recently was put Mobile premium gas as I normally use Chevron. Wondering if I got some bad gas.
2007 S600, 2007 Chrysler 300 SRT8, 2000 C5 Corvette, 2017 Mustang GT, 2023 300C, and a 2019 Lincoln
Could easily be bad gas. I'd run a plastic bottle of Techron through it next fillup. And if the CEL returns, I'd change the downstream O2 sensor. Especially if it is running nicely, clear the code and see if it re-occurs. And keep us informed.
When I have more info on this issue I'll post it here. I only drive the car about 4000-5000 miles per year so I haven't driven it much lately.
I filled her up with my normal Chevron Premium and took a 100 mile road trip down the highway and the check engine light came on again, but this time I got a code: P2097
The last time it was code: P2099 which never did come back after I erased it, instead P2097 popped up this time. I'm not sure what to make of it.
The car is a 2013 Mercedes S550 Base and has 90,000 miles on it and is in excellent condition. Its running very well, no issues there. Exhaust does not smell unusual, its has excellent throttle response and is getting 24 MPG on the highway at 65 mph on a 100 mile trip. Current code with a check engine light is: P2097
I bought 2 downstream Bosch oxygen sensors today and will install them tomorrow in place of the two I installed a year ago which have less than 10,000 miles on them. I also bought a bottle of Techron from Chevron to put in the gas tank but I have 3/4 of a tank right now so I'll need to wait until its empty to put that in and then the bottle says to add up to 20 gallons of gas once I put it in.
If anyone has a clue what may be causing this code, please comment.
Trim = Adaptions - the car's inbuilt tweaking to manage running conditions to optimise a specific vehicle's engine management to correct oddities in the way its performing
However the amount of adjustment is minor - its still has to keep emissions legal and still ensure the engine is operating within safe limits
Trim adjustment can get locked out because it isn't happy to further develop - as outside limits and or because a system sensor is throwing erroneous data / or just broken. Meaning it has no idea how to try and fix it
A great example could be hidden in what I was saying in the recent thread about Engine Oil
If a car was meant to have Low-SAPS 229.51 engine oil and you feed it High-SAPS 229.5 you can clog up the TWC three way cat until its no longer going to operate to manu spec
This risk is exponentially more likely where the car starts to burn a bit of oil as it ages / wears
A good starting point is always to check for technical service bulletins (TSB) for your particular vehicle. Your issue may be a known issue with a known fix put out by the manufacturer and can save you time and money during diagnosis.
AKA maybe its time to pay Mercedes some money to waste time on pointless diagnostics and flash the engine with a fake software update to turn off the light
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You might even find after dieselgate and lots of agencies taking a critical look at 'certain manufactures code' the car is waiting for a free update - they had a few in the last couple of years -- one where the external ambient temp sensor was programmed to lie - park the car for three weeks and magically on comes an engine mismanagement light
12 April 2019 USA mkt ONLY
Vehicle Model Year(s) 2012-2014
Vehicle Model Various (117, 166, 172, 204, 207, 212, 216, 218, 221, 222, 231, 251, and 463 platforms)
Total Campaign Population 212,237
The software of the Engine Electronics Control Unit (“ECU”) may not meet production specifications, which could result in a Malfunction Indicator Light being displayed while no fault is present in the control unit.
OP in one that is running well a cat efficiency code is often solved via the Italian tune up. Get on the freeway somewhere you can do three digits for half an hour to get and maintain enough heat in the front cats to burn up what ails them. If it continues and a software update isn’t the end of it you may ‘get’ to replace a catalyst or two.
Interesting. BenzNinja updated the ECU in my 2014 E63S. Maybe this is one of the fixes that came with the update. I had no issues before the update. I didn't see any specific codes referenced in the bulletin though.
I installed the new down stream oxy sensors yesterday, (old ones were a year old with approximately 6000 miles on them). I asked NAPA what the warranty on the Bosch oxy sensors were and they said a year and the guy also said they do sometimes go bad early on in their life.
I cleaned out my engine intake air filter housings which weren't that dirty and blew out the filters as they were not really dirty either. Did a thorough inspection underneath the car and I erased the P2097 CEL code. Once I burn this tank of gas I'll put the bottle of Techron in the gas tank and get it up to 20 gallons of Chevron Premium gas. I'll come back here and report my finding if the light comes back on and what code it gives.
I just entered the two codes I got on the Innova 5010 code reader on their website and this is what it says for the two codes
P2099 MERCEDES-BENZ Downstream Fuel Trim System 2 Rich
P2097 MERCEDES-BENZ Downstream Fuel Trim System 1 Rich
Based on this I guess both downstream oxy sensors are saying somethings up which makes me think it was not bad sensors, especially since they were both new 1 year ago. However I never regret putting new parts on my car provided they're not that expensive, the two Bosch oxy sensors cost me $100 at NAPA which isn't bad.
does your diagnostic kit inform you of the Engine ECU info HW and SW
if you have Xentry do a quick scan and press F8 it'll throw up details of every module
it would be interesting either way to see the date of the engine Map
you can go on https://www.nhtsa.gov/recalls to see if Merc agree it has an outstanding recall for the Engine ECU - if there is one stop spending money and get that first - on some there are up to 4 fake EML dash illumination tricks buried in the mischief they've been up to
I also replaced the two upstream oxy sensors 1 year and 6000 miles ago and because the driver side sensor is so hard to reach I'm not going to replace them since they only have 6000 miles on them. I seriously doubt all 4 were duds but for now the rear ones are brand new again. As for OEM, the ones I got from NAPA are the part number Bosch gave me on phone for the Mercedes OEM, he said the only difference was they have a Bosch logo instead of a Mercedes. I won't use after market parts unless OEM isn't available anymore but little by little I am learning the companies behind the manufacturing of parts for Mercedes.
great I see they got it under the radar - under a non-recall 'service campaign'
this is we know we got caught, but paid of the authorities successfully - thus don't have to go public and thus are free to rob owners for diagnostics to fund the work - and the ones that don't like official dealerships can spend 3 times as much fighting an impossible battle...
I would go to the dealer with the chassis number and say tell me if this service campaign was required and if so has it been applied to this vehicle - that is something they can easily do and should offer for FREE without to much of a fight
I don't have the fancy software or scan tools that the dealer has, its why I try to narrow down the issue myself before paying the dealer to diagnose the problem, however I just spent $130 on two new downstream oxy sensors not more than a 1 year old and a bottle of Techron which is my limit right now for guessing. If the light returns, Its a $300 diagnosis trip to the dealer. I typically then look at their recommendations and decide whether its a repair I can or cannot or don't want to do myself.
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.
