Brake dash light, can't figure this out

[dre99gsx]

Notice my dash has a Brake light on (RED, not orange), in addition to the orange low tire pressure and the DSC light in orange. Nothing else.

- Brake fluid is topped off. Even checked the sensor (0.8 ohm, seems low, but couldn't find a spec anywhere).
- Brake pads are good. Not the low-pad sensor otherwise I would see the low-pad light on the dash
- Parking brake is off. I know it works (on/off) since INPA software shows it switching

I suspect it could be tied to DSC light being on, which the manual states:
1. Yellow DSC light on, Yellow ABS, Yellow BRAKE = DSC problem (I don't have ABS light on, this isn't my issue)
2. The DSC warning lamp lights up together with the yellow warning lamp
for the brake system: DSC, including DTC and DBC, are malfunctioning (this doesn't seem to be my issue since I have a RED brake light, not a YELLOW)

The brake fluid sensor gets 12v, thus I know it's getting power. I even tried a variable resistor in there to fool it, but none of that worked. INPA states that the "Low Brake Fluid" lamp is ON (knowing INPA, this may be incorrect anyway).

2007 3.0Si Coupe...

[StickMon]

Not that this is much help, but the DME will light up combinations of lights that add up to something that has absolutely nothing to do with what the lights would mean individually.

For instance, I think EML, brake, and DSC means throttle position sensor failure.
Which usually turns out to actually be low battery.

DIS may be more help than INPA.

[thrak410]

I had that recently and it was the module under the passenger seat. I disconnected and reconnected the wire harness and it fixed it.

[dre99gsx]

Originally Posted by StickMon

Not that this is much help, but the DME will light up combinations of lights that add up to something that has absolutely nothing to do with what the lights would mean individually.

For instance, I think EML, brake, and DSC means throttle position sensor failure.
Which usually turns out to actually be low battery.

DIS may be more help than INPA.

Funny that you mention that... I have all three, and do have a code for stuck throttle body (and I know why...). I also have a nearly dead battery.

Shame on BMW for cryptic dash lights... I'll dig some more, but these lights don't disappear when driving and 14.0 volts coming out of the alternator, unless it will continue to light them up due it knowing the actual battery is failing? I'll grab a new one tomorrow and see what it does..

[dre99gsx]

Originally Posted by thrak410

I had that recently and it was the module under the passenger seat. I disconnected and reconnected the wire harness and it fixed it.

What module is under the passenger seat? I have a 3-wire connector just floating around under there, and a large yellow connector that seems to be very well plugged in to another connector.

[StickMon]

Pretty sure that's yaw sensor for the DSC.

[chickdr]

Originally Posted by dre99gsx

Funny that you mention that... I have all three, and do have a code for stuck throttle body (and I know why...). I also have a nearly dead battery.

Shame on BMW for cryptic dash lights... I'll dig some more, but these lights don't disappear when driving and 14.0 volts coming out of the alternator, unless it will continue to light them up due it knowing the actual battery is failing? I'll grab a new one tomorrow and see what it does..

If you are running around with a dead battery it can cause all kinds of faults. This is the first thing I would replace.

[dre99gsx]

Originally Posted by chickdr

If you are running around with a dead battery it can cause all kinds of faults. This is the first thing I would replace.

Agreed, although once the alternator is properly charging and I'm on the road, I would assume any dash lights regarding battery would be long gone.

While on topic, under the passenger seat, three-pin connector is floating around: Brown, Gray and Green/Violet. Chances this is the passenger seat occupancy connector which was left disconnected from the original owner? Trying to rule out YAW sensor connection (which from the manual, shows as 6 pin connector...)

[StickMon]

Yep. Yaw sensor looks like 6-pin
http://www.zpost.com/forums/showpost...3&postcount=10
https://www.ecstuning.com/b-genuine-...r/34526764018/

[dre99gsx]

Thanks for the link, definitely not the Yaw sensor. I suspect it is the occupancy connector. if anyone can confirm the connector/colors (should be easy to look down there?). BMW Wiring diagrams don't show what I need to see...

Back on topic, new battery installed, problem still exists. Installing DIS software and going to dig in deeper. I've now put my car in "Transport Mode" upon removing the battery (lovely!).

[Clearancediver]

If you are disconnecting wiring under the seat you had better disconnect the battery first. Doing so without disconnecting the battery will set codes/faults that can only be cleared with software. The fault lights associated with many faults can only be cleared with software...not driving the vehicle.

INPA as well as DIS can clear those codes... I like INPA for that myself. I and my son bought Rheingold INSTA (D) and (P) and have to learn how to use that now.

If your car went into transport mode, it's because of low voltage from old battery... not from installing new battery...

[chickdr]

You can deactivate transport mode as well. The dealer was supposed to do that as part of the PDI but many did not which leads to the situation you are in now.

[dre99gsx]

Got DIS, removed transport mode. Found the real cause of the issue. I kept ignoring the "CAN communication error" coming from INPA's inability to communicate with the DSC, and further, DIS. Stupid me: When doing the 2JZ swap, I forgot to join the CanH and CanL pins at the IVM box in the engine bay, thus the DSC was never communicating with the DME or anything else for that matter (even though I was able to program the DSC via NCSexpress).

Now, I get Yellow BRAKE and traction control dash lights, but this is related to a check engine light. In good shape, thanks for the suggestions everyone.

[chickdr]

Glad you got it sorted!