94 530i random warning codes

[SunshineTrent]

94 530iT

On an hour drive yesterday, gauge cluster started showing me a brake lt circuit failure. Soon after, lots of other random warning codes flashed. Tire failure, door open, hood open, esd regelt, asc from what l remember off the top of my head.

None of these codes were true. I have an extra CCM, and read that this relay was the issue, so l swapped it out but this didn’t fix the problem. Where should l look next? Gauge cluster, fusebox wiring? Is there another module that can cause this?

Codes do not come on until about 15-30 min of driving. Brake lt circuit is the only one that is persistent after they all flash. 

Any ideas appreciated!

Trent

[jc43089]

A failing battery?  Or alternator?  Low voltage can cause all kinds of wacky things.  A lot of the monitoring systems are monitoring current, if the voltage is not right the current isn't either and can trigger all kinds of warnings.

[Jdesign]

I would get the battery tested and go from there. It also could be a loose plug somewhere and doesn't happen till you hit a bump.

[HipMF]

What have you tried so far? This is a fairly common problem on these cars. Mine did it randomly every month or two. The interweb says that the brake switch on the pedal is the most likely cause.

[RobZR]

Another common failure that throws random errors is a cracked fusible link by the battery. as it heats up it will open or create so much resistance that the the voltage drop creates havoc in the electrical system.

[SunshineTrent]

Thanks for the replies. 

The only thing l have done was changing the ccm, since that was what l read on just about every forum post about the issue. Problem occured for the first time just a couple days ago. It’s hard to search for this because most of the threads/results are how to fix the individual codes.

I’ll have to get out the ol multimeter. As for loose connection from hitting a bump this is also very possible. Seems to only go crazy with loads of codes when driving on a less than ideal road.

As for the brake pedal switch l don’t think that is the case because the circuit code didn’t show up until all of the others did as well, and the brake lights are working fine along with everything else it says is wrong. However since it’s the only persistent code, and I’ve read that it comes on even when the lights do work when testing, whos to say they do every time. it’s possible that one is a real issue.

Thanks again!

[straight6pwr]

as HipMF stated, I had this happen once in a blue moon, but never could even look into it because it would be gone before I could.

for the brake light circuit code, try re-seating the taillight brake bulbs. historically, that always worked for me. I think they shake loose and the slight short causes the code.