[venkatshan]

Looked around and there is no direct answer to fixing 4BCC in e90 with a 10K resistor. Hope this is helpful to someone.

Used a 10K resistor across connectors of the passive level sensor - which is close to the rear bumper.

STEP 1: Soldered a 10K 1/4 watt resistor ends to a 23 AWG copper wire and apply heat shrink wrap.

For anyone wondering about 1/4 watt is plenty. Here is the math: 10K across 12~14V would pass about 1.2 ~ 1.4 MA that would be about 14 ~ 20 MilliWatts.

STEP 2: Punch two holes with a tiny(match wire thickness) red-hot needle on the wider end of the connector cable.

STEP 3: Insert the resistor/wire and bend them into the connector electrical pins. Make sure separate the wires and route it appropriately so they wouldn't get got in the clips.

It took about 30 mins to complete the work.

Followed this thread to access the top of the Tank. No need to drop the tank.
https://www.e90post.com/forums/showpost.php?p=17070863

1. Drop the exhaust
2. Remove just one heat shield near the rear bumper.
3. Undo two 16 MM nuts holding the tank and a small nut on the passenger side - forward - tank needs support.
4. Top plate should come off now.

Drove for about 50 miles after the fix and it seems to hold up so far.

[Yozh]

Nice workaround. Seems 10k resistor is for everything.