BMW E31 850i Stomp Test Procedure (840i, 750il, 525i, others)

Here's how you get the check engine codes out of an early E31 without any special diagnostic tools. My car is a 1991 US model 850i, but this does work for 8 series from other years, and also works for the E32 7-series (735i, 750iL), as well as the E34 5-series.

Procedure:
1) Turn key to run, but not start
2) After EML light goes out, depress accelerator pedal to the floor and release, 5 times in about 5 seconds.
3) Car will confirm with a long flash, then begin flashing out your codes.. if it doesn't, turn the key off and repeat
4) Each code repeats itself, so you have to stomp 5 times to get the next code

Note: For the V12 engines you'll have to do the procedure twice, once with 5 stomps to get bank one codes, and then 6 stomps for Bank 2. (cylinders 7-12)

Also note: bank 1 codes all start with 1, bank 2 codes start with 2. E.g. 1264, 1222 on my car in the video, and bank 2 reported only 2444 (no codes). It's also important to realize that due to the crossed intake design, the intakes are on the opposite side of the engine bank in question. (Bank 1, 1-6 on the left, bank 2, 7-12 on the right IIRC)

Once upon a time I thought I figured out a way to clear the codes by pressing and holding the pedal, but don't recall exactly! Disconnecting power clears codes in early models though.

Trouble? Make sure your check engine light actually works! Sometimes they burn out, other cars (European) may not even have the CEL bulb.

Please don't ask me for the meaning of the codes, just Google "BMW stomp codes" or check any number of repair manuals!

Edit: Apparently I said I had an 850iL.. I'm not even sure what that would look like!!