Firstly sorry for the life story here, hopefully someone is able to point me in the right direction to hopefully get this solved without being too costly, also just to point out I am UK based.

My partners 2020 CX-5 2.2 Skyactiv D has decided to throw an engine management light and is also complaining of engine oil level too high. For a bit of context the car is serviced yearly at approximately 9000-10000 mile intervals. It's last service was done in December last year and it has done approximately 4000 miles since. The car itself has done about 60000 miles and the daily commute is a 9 mile each way 20 minute journey that mostly consists of motorway. This isn't the first time we've had the high oil warning come on but it is the first time there has been an engine management light too. Last time was maybe 9 months ago and we had the oil level corrected by the garage that does the services.

Yesterday I followed the Mazda stated procedure for checking the oil level manually and as you can see in the picture below I would say it is ever so slightly over the max line, I've read about the oil dilution issues causing rising oil level problems and that the X marker on the dip stick is Mazda's maximum allowable dilution. I wanted to know if this meant I had a decent amount of wiggle room still before an oil change would be needed or should I realistically be looking at having it changed immediately. It does seem slightly extreme to me to need to have it changed after 4000 miles when the service schedule says 12 months or 12,500 miles. As this isn't the first time we've experienced the high oil level issue I'm wondering if the sensor is just that spot on or based on the fact the level is pretty much at the max line and not near the X dilution line it could perhaps indicate a faulty sensor.

I put a cheap OBD2 reader on just to see what information I could gather regarding the engine management light, naturally it did kick up a code related to the high oil level. There were also additional codes which I will put below as well as a picture, a quick google for each of them and the alleged most common cause for multiple is some form of sensor malfunction. I did want to ask for advice regarding getting a reasonably priced and recommended OBD2 reader and program or app for Mazda. I just used a cheap generic one that I had lying around, I couldn't get it to connect to the paid for app FORScan lite on Iphone and ended up using the free car scanner Iphone app instead.

The codes are as follows:

P24C6 (00) - From what I read this is linked to a faulty particulate matter sensor

P252F (00) - This is the high engine oil code, most commonly caused by diesel fuel dilution from failed or interrupted regeneration attempts

P1640 (00) - I was a little more stumped with this one, it seems to indicate that powertrain DTCs are available in another control module such as the dosing control unit. My little scanner wouldn't read the DCU. common causes allege to be faulty NOx sensor or issues with the DEF/UREA system.

P1260 (00) - This is an archived code that I think is just perhaps related to when the key battery was on its way out and needed replacing

P0421 (00) - This one is another archived code but has me the most concerned. Google informs me that its common causes are either a failing catalytic converter, possible exhaust leak or yet another possible sensor issue, this time one of the O2 sensors.

I realise there is possibly quite a lot going on here and we are definitely weighing up simply taking it to a Mazda specialist over main dealer as prices are just astronomically high, but even just to have either of them run diagnostics is priced at £150-£200 which I presume is using their OBD2 tools and programs and formulating a proposed work plan based on the codes returned. I'm just trying to ascertain if I can get on top of some or all of this myself, I would say I'm semi car literate but definitely have a stronger experience and knowledge of working on early 2000s cars and not the more modern or Japanese cars. Any and all advice is appreciated and if you require more information don't hesitate to ask.

My initial plan if I was going to try to tackle this was to start by getting a better scanner and program for this specific brand of vehicle. Perform an oil and filter change followed by a reset to the oil maintenance monitor and oil data system for the oil high warning. Remove and attempt to clean up the PM and NOx Sensors. Clear the codes and then take it for a decent run to do a regeneration cycle and see what still persists after that.

Thanks for the help.

 

Welcome to the forum

Honestly with that many DTC and likely more you don't know how to locate you need to go to a service shop that has a Certiidife Diagnostic Technician and have them scan your ECU and give to a short run data log and then give you an assessment. I also see that you have some DTC that are older than other and likely caused the DTC to activate them which convolutes more of finding the root cause.
I do strongly suggest that you do not replace any parts or do any cleaning of them unless you know how to check them first! You will more than likely cause additional unresolved issued that will just add to more problems.
Its not about the scanner you are using (unless it is a blue tooth type) but that you don't have the learned skills. If it were then simple, then we could all be doctors.