+18 E46 Check Engine Light References. It will show hard fault codes and any pending codes that not trigger a check engine light. Web if your bmw e46 hasn’t yet displayed the yellow “eml” indicator, it won’t be long.
I think that sensor can trigger a cel. The check engine light came up a few days ago and went to a mechanic which put the tester on my car, result was: Ordered an oem sensor from fcpeuro and threw it on and now the lights gone.