Mix Error codes

[MSAL200]

Have few error codes:
2AF2, 2AF4, 2AF6, 2AF9 - Nox issues
2A99 - Crankshaft - exhaust crankshaft
2EF8 - Map Thermostat activity ion
29E0 - Mixture Control

I have done some online research with these codes and find out that they may indicate different issues.

Shall I tackle these issues separately or cleaning/changing the Nox sensor may fix them all?

[bms5]

I would only be concerned about the NOx issues. If you don’t, the poor efficiency of the SCR system could trigger the ‘Incorrect Diesel Exhaust Fluid - no start in 323km’ message.
Check that the delivery module nozzle is not caked with DEF residue. It’s quite easy to remove and clean. When it becomes partially blocked, an inadequate amount of fluid is delivered to the catalyst and the NOx sensors can’t tell the difference between incorrect fluid and not enough fluid.


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[White94RX]

BMW put out a diagnostic tree about NOX sensor codes. It specifically states checking the thermostat for proper operation. If the engine runs too cool, it will increase NOX. You may have several issues, but since you do have a thermostat fault code, I would definitely be replacing it.

Aside from that, we didn't get any diesel option other than the 335D, so I don't know much about yours (assuming it is the 318 in your profile?)

[bms5]

BMW put out a diagnostic tree about NOX sensor codes. It specifically states checking the thermostat for proper operation. If the engine runs too cool, it will increase NOX. You may have several issues, but since you do have a thermostat fault code, I would definitely be replacing it.

Aside from that, we didn't get any diesel option other than the 335D, so I don't know much about yours (assuming it is the 318 in your profile?)

Good point about the thermostat. It’s so common to see a map cooling fault code that doesn’t affect normal operating temperature but if the engine temp is too cool, that is indeed a good place to start.


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[MSAL200]

I would only be concerned about the NOx issues. If you don’t, the poor efficiency of the SCR system could trigger the ‘Incorrect Diesel Exhaust Fluid - no start in 323km’ message.
Check that the delivery module nozzle is not caked with DEF residue. It’s quite easy to remove and clean. When it becomes partially blocked, an inadequate amount of fluid is delivered to the catalyst and the NOx sensors can’t tell the difference between incorrect fluid and not enough fluid.


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Thanks for the reply bms5, It is not a Diesel engine. It is 2 Litre petrol engine. Is there anything that you can suggest in petrol engine to clean to see if helps to get rid of the fault codes? ( already taken out the Nox sesor and cleaned it but didn't work )

[MSAL200]

Thanks for the replies guys.
I have taken out the Nox sensor, cleaned it and deleted the codes. However the following codes showed after a short journey:
2EF8 - Map Thermostat activity ion (after 10 miles Journey ) then 2AF2, 2AF4, 2AF6, 2AF9 - Nox issues ( after 20 miles journey ) (Using Creator 310+ code reader )

Found a receipt in the car, previous owner changed the water pump in Feb 2020 from a small garage. ( doesnt mentions anything about the thermostat)

New Nox sensor is very expensive to buy ( £450 from BMW & £200 from Ebay ). I don't want to spend all that money change the nox sensor ( easy to change ) but left with the fault codes again. But thermostat is not too expensive to change.

Should I change that thermostat first to see what happens? or all that problem caused by the faulty Nox sensor and if I change the nox sensor all the codes will be gone?

Note: The car has a 2 Litre petrol engine, I think it is called N46 engine.

[White94RX]

I would definitely change the thermostat. Regardless if it fixes the NOx codes, it still needs to be changed since it’s setting codes.


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[MSAL200]

Hi Guys. I have a bit update on this car.
I took the car to BMW and paid for them to check it. They have said that timing chain needs to be changed. They also said that there is a miss fire in the 3rd cylinder. The new timing belt might fix the miss fire as well as fixing the cold start problems. If miss fire continues, they may need to change spar plugs + coils or the injector to fix the miss fire in the 3rd cylinder. New timing belt £1800 and if it needs further parts to fix the 3rd cylinder another £600.

Shall I pursue to fix this issue from an in-depended garage or shall just get rid of the car? ( The guy from the BMW garage said I may experience other problems with other parts in the engine after couple of years even if I pay and get the new timing chain now. He advised me to change the car. )