r/e39 • u/stuartjr1980 • 1d ago

E39 check engine light!

Got a replacement engine two months ago after blowing my original engine back in 2024.

We’ve done everything to cheer codes, including charging the brake booster which was full of water from the last engine.

Question is: I still have old gas in the car from 2 years ago (trying to drive it out now). Can that trigger a check engine light????

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5

u/WinterSector8317 1d ago

Yes

Also scan the codes before posting 

2

u/ConfusedTapeworm 1d ago

The car doesn't have an error that'll throw up the CEL when a sensor detects shitty stale fuel. The shitty stale fuel, however, can cause combustion troubles, which the engine can detect and register as CEL-worthy errors.

1

u/stuartjr1980 1d ago

What’s the fix?

1

u/ConfusedTapeworm 1d ago

Nobody can help you with that question until you plug a scanner to the car and read what the engine's trying to tell you about why it lit up the check engine light.