Fault codes advice

Jcm325 · Post by **Jcm325** » Sat Jan 13, 2024 2:03 pm

Hi , got the dreaded light on the dash today and plugged in my code reader and I got a bunch of codes.
The light came on the day I bought the car and basically the same group of codes have come back, this has taken approximately 3 months and roughly 800 miles.
No obvious issues to the running of the car and nothing untoward in the engine bay, no split hoses or anything disconnected.
Basically I need to know what to do next?
Replace the sensors showing faults?
Any ideas appreciated
See photos for codes

j3nks79 · Post by **j3nks79** » Sat Jan 13, 2024 3:00 pm

First of all you need to check for any leaks from the exhaust. Common on the downpipe joints.
Could just be a simple fix before you start throwing money on sensors

enuff_zed · Post by **enuff_zed** » Sat Jan 13, 2024 4:31 pm

Which light did you get on?
EML?
The fact you reset and then it took that long to come back tiers in nicely with colb's description of what happens when you get an air leak.
The DME keeps richening the mixture as the unmetered air makes it think the engine is running too lean. Eventually it runs out of adjustment and the light comes on.

Jcm325 · Post by **Jcm325** » Sat Jan 13, 2024 7:17 pm

I didn't get EML
I got the other yellow one shaped like an engine
So do we think air leak (vacuum) in the engine bay or exhaust leak

enuff_zed · Post by **enuff_zed** » Sat Jan 13, 2024 8:24 pm

Jcm325 wrote: ↑Sat Jan 13, 2024 7:17 pm I didn't get EML
I got the other yellow one shaped like an engine
So do we think air leak (vacuum) in the engine bay or exhaust leak

First step is always to check every inlet pipe for air leaks

colb · Post by **colb** » Sun Jan 14, 2024 12:36 am

The yellow engine shaped warning light is the Engine Management Light (EML). Since you have fuel trim codes look for split or holed vacuum hoses/pipes and inlet boots. If you cant find any try a smoke test that should find ay leaks.

Jcm325 · Post by **Jcm325** » Sun Jan 14, 2024 9:19 pm

Ok thanks will do a smoke test...
If the light i got is engine management light then what is the other light next to it with the letters EML?

Mike6 · Post by **Mike6** » Mon Jan 15, 2024 6:35 pm

I got those codes and reset them. Lasted a while but kept coming back . Its the heater element in the sensor which it seems to fail intermitently . As the sensors are located right next to the troublesome exhaust joint it could be that is letting air in . Either way unless you are houdini and a glutten for punishment get a garage to fix it.

Mike6 · Post by **Mike6** » Mon Jan 15, 2024 6:35 pm

I got those codes and reset them. Lasted a while but kept coming back . Its the heater element in the sensor which it seems to fail intermitently . As the sensors are located right next to the troublesome exhaust joint it could be that is letting air in . Either way unless you are houdini and a glutten for punishment get a garage to fix it.

Jcm325 · Post by **Jcm325** » Mon Jan 15, 2024 9:29 pm

Hi thanks for your input,
Are these sensors the same for both sides ie Bank 1 and Bank 2? Also is there a good supplier for these apart from bmw!!!!
Thinking about biting the bullet and just going for it...
Had a visual check today can't see any issues with inlet hoses etc
I'm calling the garage tomorrow about a smoke test

Jcm325 · Post by **Jcm325** » Mon Jan 15, 2024 9:33 pm

Probably not my last stupid question but is it safe to drive currently?

colb · Post by **colb** » Tue Jan 16, 2024 10:14 am

If its the heater circuit in the sensors thats gone bad then only option would be to replace them, only fit oem sensors such as Bosch, do not buy cheap or those universal types that have to be wired in. Once fitted run car up to temp, clear any codes with your scanner then take a look at live data on the exhaust sensors to see what they are doing, you should see a nice wave form in graph view as the sensor ranges up and down the voltage range (Pre Cat Sensors). Post Cat sensors will look quite static unless they are picking up bad exhaust gases.

Jcm325 · Post by **Jcm325** » Tue Jan 16, 2024 10:36 am

Hi thanks for the info
From my limited research I think the sensors are at fault as I'm not getting the p code's which I think lean towards vacuum leaks etc
Plus the heater circuit faults are identified with the check engine light on.
Can anyone recommend a reputable supplier for these and confirm if both sensors are the same?
I've looked at realoem and I think they're the same but when I Internet search the part numbers and lengths etc vary considerably so I don't want to buy the wrong ones.
Also can I cause any damage if I drive the car with the lights reset?

Mike6 · Post by **Mike6** » Tue Jan 16, 2024 7:12 pm

I got both post cat sensors from AutoDoc, they looked exactly the same but had different colour leads presumably for fitting purposes. The pre cat sensors will have shorter cables but not sure whether the sensor themselves are the same. They seem to have different code numbers but that may just relate to the cable colours. Buy Bosch ones from Autodoc, a reputable supplier used by a lot of forum members. They are based in Germany so parts will take a week or so to arrive but they are competatively priced.
I would think it safe to run your car and just code out the EML which I did, unless it come back immediately. I didnt notice any real difference in performance when the light came on, but others may disagree.
Get them replaced in a garage, nearly killed me trying to get the old ones out.

enuff_zed · Post by **enuff_zed** » Tue Jan 16, 2024 7:16 pm

Yep Autodoc are good, and their delivery times have got better lately too.
Worth thinking if you need anything else to make it high enough to get free postage.
If you are not already signed up to their app, PM me your email address and I'll send you a link that will get you a few quid off your first order.

(And because someone is bound to have a dig, I'll be up-front and say that I will get a bit off my next order for introducing you too.)

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