CEL on after going Catless (With tune)

[ExoticM3]

All right! I'm fed up with this CEL light on my dash every time I drive. I'm stage 2 fully catless and tuned by Alpinemss. Please... can you guys give me some possible solutions.

I heard that replacing your O2 sensors is a temporary fix by multiple individuals and they go bad at 3-5k miles.


2782 - Secondary-air pump, activation, eledrical diagnosis
2778 - DMTL heating
2777 - DMTL Valve
2739 - Air-mass sensor, secondary air, electrical diagnosis
27C5 - Air-mass sensor, secondary air, plausibility
2748 - Oxygen sensor before cat, evaluation module in control module, bank 1
2861 - Transmission input-speed sensor/slipping clutch
2776 - DMTL pump
274A - Oxygen sensor pump.current calibration fault before cat converter, bank 1

[M3SQRD]

Your CEL is on because you deleted the stock cats. Your Alpine tune should be able to suppress the CEL but you’ll fail emissions even with the CEL turned off. You weren’t expecting the CEL to not come on when you removed the cats? The stock cats clean up the exhaust output so post-o2 sensors are expecting to read cleaner than pre-o2s so when this is not the case you’ll get a CEL.

[ExoticM3]

Originally Posted by M3SQRD

Your CEL is on because you deleted the stock cats. Your Alpine tune should be able to suppress the CEL but you’ll fail emissions even with the CEL turned off. You weren’t expecting the CEL to not come on when you removed the cats? The stock cats clean up the exhaust output so post-o2 sensors are expecting to read cleaner than pre-o2s so when this is not the case you’ll get a CEL.

No, I was not expecting the CEL to come on after removing my cats because the tune would clear it. That’s why I’m here because even after the tune I still have the CEL light. I don’t care about passing emissions I live in a state where it doesn’t matter.

[nycplumber]

Clear it and see if it comes back. That used to happen when I was NA with the ESS tune and then switched to Epic and never had an issue

[Redd]

Go back to stock tune and test. That will tell you very quickly if the tune is the issue.

[ExoticM3]

Originally Posted by nycplumber

Clear it and see if it comes back. That used to happen when I was NA with the ESS tune and then switched to Epic and never had an issue

I cleared it thousands of times and unfortunately it comes back…

[ExoticM3]

Originally Posted by Redd

Go back to stock tune and test. That will tell you very quickly if the tune is the issue.

So, you think going back to stock file with not having cats will remove the CEL? This doesn’t make any sense honestly

[GOFAST M3]

You need to talk to Alpine, and see why you still have a CEL.

[ExoticM3]

Originally Posted by GOFAST M3

You need to talk to Alpine, and see why you still have a CEL.

I did and he said it’s cause of the DMTL and secondary air mass stuff which is weird….

[BP709]

Originally Posted by ExoticM3

I did and he said it’s cause of the DMTL and secondary air mass stuff which is weird….

How is it weird? Not a single fault that you listed has anything to do with not having cats or the tune. Flash back to stock and you’ll have all those faults plus catalytic converter efficiency faults. You need a new DMTL pump, new bank 1 pre catalyst oxygen sensor and need to test the secondary air pump to see if it activates but there’s a strong possibility it is bad as well as the air mass sensor for secondary air unless you have it disconnected for some reason.

[M3SQRD]

Originally Posted by ExoticM3

No, I was not expecting the CEL to come on after removing my cats because the tune would clear it. That’s why I’m here because even after the tune I still have the CEL light. I don’t care about passing emissions I live in a state where it doesn’t matter.

Talk to Alpine about your tune because the post-O2 sensors should be turned off. However, I believe (correct me if I’m wrong) it’s possible to get a CEL on a post-O2 if it goes bad.

[smokinjoe64]

My experience/feedback for consideration...

Struggled with Alpine Stage II CELs as well. Took a while & parts to get sorted.
Although different codes, similar in some ways. Also, emissions codes [runnin' rich].
Suggest be precise with your M3 config description to Alex...it does make a difference in tune sent to you.

Parts merry-go-round replacements [over a~3K mls span] :

• Primary O2 (3x)
• Secondary O2 (2x)
• Plugs (2x)
• Cam position sensors (1x) => Installed last; change seemed to eliminate recurring CELs; no issues since then

My config in 'signature' below

[ExoticM3]

Originally Posted by smokinjoe64

My experience/feedback for consideration...

Struggled with Alpine Stage II CELs as well. Took a while & parts to get sorted.
Although different codes, similar in some ways. Also, emissions codes [runnin' rich].
Suggest be precise with your M3 config description to Alex...it does make a difference in tune sent to you.

Parts merry-go-round replacements [over a~3K mls span] :

Primary O2 (3x)
Secondary O2 (2x)
Plugs (2x)
Cam position sensors (1x) => Installed last; change seemed to eliminate recurring CELs; no issues since then

My config in 'signature' below

Did that fix the CEl? Thank you for the suggestion

[ExoticM3]

Originally Posted by M3SQRD

Talk to Alpine about your tune because the post-O2 sensors should be turned off. However, I believe (correct me if I’m wrong) it’s possible to get a CEL on a post-O2 if it goes bad.

He just tells me I have to fix mechanical issues, and says it’s not a tuning problem. I’ll change the O2 sensor pre cat and see where that gets me.

[HeavyArmZ]

I had similar issues when I went catless with Alpine tune. New o2 sensors, secondary air pump, check valves did not get rid of fault. I changed out the DMTL pump and codes never returned. Part is cheap and easy to replaced.

[smokinjoe64]

Originally Posted by ExoticM3

Did that fix the CEl? Thank you for the suggestion

Affirmative

[ExoticM3]

Originally Posted by HeavyArmZ

I had similar issues when I went catless with Alpine tune. New o2 sensors, secondary air pump, check valves did not get rid of fault. I changed out the DMTL pump and codes never returned. Part is cheap and easy to replaced.

Went and purchased the part and even got the rubber grommet from FCP Euro. Hopefully this resolves it. Will update

[ExoticM3]

Originally Posted by smokinjoe64

Affirmative

Originally Posted by HeavyArmZ

I had similar issues when I went catless with Alpine tune. New o2 sensors, secondary air pump, check valves did not get rid of fault. I changed out the DMTL pump and codes never returned. Part is cheap and easy to replaced.

I changed the DMTL pump and still getting a 2777, 2778 code and also the secondary air mass code. I cleared adaptions and cleared errors. Not sure why I’m still getting the code

[TboneS54]

Have you scanned the code? If it says o2 or catalyst, then it's the tune. Otherwise, it might say it's SAP (cold start, air pump) or gas cap or fuel tank or whatever, then go from there.

Is that list in your OP all of the codes that are showing? That's a lot and I would have a hard time believing the coincidence that all that hardware went bad at the same time.

The suggestion to flashb ak to stock was a good one. I would do so, reset codes, drive it a few cycles and see if anything besides o2 realtes codes come up. If so, then it's alpine's tune.

[ExoticM3]

Originally Posted by TboneS54

Have you scanned the code? If it says o2 or catalyst, then it's the tune. Otherwise, it might say it's SAP (cold start, air pump) or gas cap or fuel tank or whatever, then go from there.

Is that list in your OP all of the codes that are showing? That's a lot and I would have a hard time believing the coincidence that all that hardware went bad at the same time.

The suggestion to flashb ak to stock was a good one. I would do so, reset codes, drive it a few cycles and see if anything besides o2 realtes codes come up. If so, then it's alpine's tune.

Got it I’ll go and flash back to stock and see what happens.

[el_m3nace]

Update?

[ExoticM3]

Originally Posted by el_m3nace

Update?

Didn’t change anything, I’m going to get a tune by EPIC after the winter passes by. They provide a tune where you code out CEL and SAP