DSC, ABS, and brake light on highway

[TwinsPoppa]

Originally Posted by Ricky Bobby

OK so here are the results of my scan today via GT1:

I must note that at the time of my scan that the "trifecta" was not present on the dash, and it was not on at the start of my car today, nor the entire time driving home. Does that mean the "trifecta" faults would not show up in a scan? I'm under the impression that past faults are stored even if the light is not on.

DSC 74 - Brake Light Switch (DME/DDE) - DSC actively switched no ABS Control

DSC 75 - Brake light switch, line - DSC actively switched no ABS Control

DSC 5A - DSC Brief power interruption, DSC actively switched no ABS control - Power supply


Then I have 2 DME faults:

DME 27 - Plausibility signal brake light switch

DME 78 - Plausibility accelerator and brake pedals simultaneous activation
(not sure if these are related to DSC module)


We cleared all faults, and did a re-scan and nothing returned except for this fault:

BD IKE - Electronic braking-force distribution


crossing my fingers that its not a module problem thanks for all help guys and thanks to Neil "neilrmp" for his help today!



EDIT: My DSC module faults seem not to correspond with the ones Bluebee posted in her comprehensive thread on Bimmerforums, i.e. my DSC fault 74 and 75 did not read as the description on that thread, here are the faults she posts:

BMW ABS/ASC Bosch 5.7 Table of error codes:
5 Right Rear Wheel Speed Sensor
6 Right Front Wheel Speed Sensor
7 Front Left Wheel Speed Sensor
14 Solenoid Valve Relay (check fuses 17 & 33)
15 Pressure Sensor/Pump Error
21 Module Memory Failure - ABS/ASC module is faulty
23 Incorrect Coding - ABS/ASC module is faulty
24 Wrong Impulse
30 Left Rear Wheel Speed Sensor
31 Open Right Rear Wheel Speed Sensor
32 Open Right Front Wheel Speed Sensor
33 Open Left Front Wheel Speed Sensor
50 Right Front Outlet Valve - ABS/ASC module is faulty
51 Left Rear Outlet Valve - ABS/ASC module is faulty
54 Left Front Inlet Valve - ABS/ASC module is faulty
55 ASC Intake Valve - ABS/ASC module is faulty
58 Gear Box Control Unit (CAN bus error)
59 DMER1 (CAN bus error)
61 Steering Angle Sensor Identification
66 Speed Sensor Voltage Supply
67 Intermittent Interference
75 Engine Speed Fault from DME
81 Pressure Sensor
82 Open Yaw Rate Sensor
86 ASC Cut-off Valve Rear Axle
88 Precharge Pump
89 Low Voltage
90 Temporary System Deactivation
94 DDE Fault/Yaw rate sensor
97 Steering Angle Sensor
10 Brake Light Switch
108 SN Control
112 Open CAN to Instrument Cluster
114 Pressure Sensor Offset
117 Brake Light Switch Failure
118 DME Status-Internal Error

I would not have cleared the faults if they were present. I would have just followed the test plan for each and it may have confirmed some things.

Maybe you have a bad brake pedal switch causing intermittent faults. Maybe it could be a fault somewhere else and the brake pedal switch is just not getting the signal from a sensor - and that's why you're getting the fault in the brake pedal switch (which may not be faulty at all).

That condition seems to be why things are being turned off and so you get the trifecta of lights.

See where I'm going with this?

Since you cleared them its too late now but if you get the faults again follow the test plan.

All things SEEM to indicate a bad brake pedal switch but who kows. Maybe look at it and see if its loose or something. I don't see anything that sort of points to a module except maybe this one.

"DSC 5A - DSC Brief power interruption, DSC actively switched no ABS control - Power supply"

Not sure how you get a power interruption to the DSC/ABS module.

The brake force distribution I would not pay attention too much. I had that on my GT1 and I've seen it on others and I think its a glitch from the software or the DME needs a newer software update/DIS. I had followed what weasel told me prior and didn't help with that.

As a general catch-all .... have you had your alternator/battery replaced or are known to be good?

EDIT: I found a thread with that DSC power interruption and it turned out to be a bad steering angle sensor. Another possibility but I would follow-up with the brake pedal switch first, then the sensors like the wheel speed sensors and the steering angle sensor.

http://www.xoutpost.com/bmw-sav-foru...-sluggish.html


EDIT2: The item in question I believe is called a "Brake Stop Switch". Another example of it causing similar symptoms.

http://www.xoutpost.com/bmw-sav-foru...ed-sensor.html

[Ricky Bobby]

Originally Posted by TwinsPoppa

I would not have cleared the faults if they were present. I would have just followed the test plan for each and it may have confirmed some things.

Maybe you have a bad brake pedal switch causing intermittent faults. Maybe it could be a fault somewhere else and the brake pedal switch is just not getting the signal from a sensor - and that's why you're getting the fault in the brake pedal switch (which may not be faulty at all).

That condition seems to be why things are being turned off and so you get the trifecta of lights.

See where I'm going with this?

Since you cleared them its too late now but if you get the faults again follow the test plan.

All things SEEM to indicate a bad brake pedal switch but who kows. Maybe look at it and see if its loose or something. I don't see anything that sort of points to a module except maybe this one.

"DSC 5A - DSC Brief power interruption, DSC actively switched no ABS control - Power supply"

Not sure how you get a power interruption to the DSC/ABS module.

The brake force distribution I would not pay attention too much. I had that on my GT1 and I've seen it on others and I think its a glitch from the software or the DME needs a newer software update/DIS. I had followed what weasel told me prior and didn't help with that.

As a general catch-all .... have you had your alternator/battery replaced or are known to be good?

EDIT: I found a thread with that DSC power interruption and it turned out to be a bad steering angle sensor. Another possibility but I would follow-up with the brake pedal switch first, then the sensors like the wheel speed sensors and the steering angle sensor.

http://www.xoutpost.com/bmw-sav-foru...-sluggish.html


EDIT2: The item in question I believe is called a "Brake Stop Switch". Another example of it causing similar symptoms.

http://www.xoutpost.com/bmw-sav-foru...ed-sensor.html

Thanks Twins,

The battery is known good as far as I can tell, it is only 1.5 years old (replaced right before I bought car) and I have never had problems with it.

The alternator is original as I do not recall previous owner saying he replaced it, I have a decent amount of pixels out on my display, so I will get it fixed first and then unlock the OBC and monitor voltage via the alternator test, but I'm unsure of it being faulty to be honest, I have really had no other issues to speak of to date, no problems with lights or overcharging, undercharging symptoms etc so I can almost rule that the alternator is good.

You're right, the only code that worries me is the brief power interruption 5A, and if the lights come back on I will know to go back to Neil and have a re-scan and this time we will follow the test plan to rule out other possibilities.

I did not test wheel sensors and steering angle sensor, etc since I was not throwing codes for them, I was figuring no problems there at the moment.

On my old VW when a brake light switch was bad, it would leave brake lights illuminated all the time when driving, something these cars don't do. I believe the switch might be under 30 bucks so I may replace just to be sure of a new part, or I may just clean the connections at the pedal switch with electronic cleaner to rule out anything like that first and foremost.


Thanks guys for all the input so far,