DSC and Brake Pressure sensor replacement. E85

T

Toe-side

Senior member
Replaced pressure sensor 1 this morning (pressure sensor 1 fault code and yellow DSC and brake warning yellow also)
Pressure sensor 1 is the rear braking system and is the sensor closest to the font of the car. Pressure sensor 2 is the front braking system and is closest to the bulkhead.

Replacement with a second hand sensor was a literally a 2 minute job. Both pressure sensors are the same part and are shared with the E46 range so plenty available in breakers. New sensor IRO £95 btw.
Link to thread http://z4-forum.com/forum/viewtopic.php?f=3&t=36590&p=1028091&hilit=pressure+sensor+1#p1028091

Place some one in car applying light pressure to the brake pedal during the removal.
Disconnect plug (ignition off)
Place rags under the sensor area to catch any brake fluid loss.
Unscrew the sensor (I used an adjustable with large jaw opening as access for a large adjustable is tight body is 27mm hex ) and immediately reinsert the replacement sensor. As quickly as possible to avoid fluid loss and air ingress.
Tighten and reconnect sensor plug (ignition off).
Start car. Move car checking brakes are functional first :!:
Switch off ignition and on second attempt with ignition back on the lights should be clear. Mine needed some movement of the car and ignition off and on again to reset.
:thumbsup:
 
Thanks for the write up. My sensors fault once every couple of months and the diagnostic is pointing to this.
Any need to bleed the system or change the fluid after fitting?
 
I haven't needed to. Brakes feel as before.
Its important to minimise time with the sensor out as fluid is slowly issuing due to the pressure on the pedal.
Once slackened the sensors spin off and on by hand/fingers so it can be done very quickly this minimises the chances of any air ingress.

:thumbsup:
 
Thanks for the writeup! I'm going to try this on my MY03 Z4 3.0i. The warning lights just started to come on recently, after the car was in storage for about 9 months.
 
thanks for this guide - had the sensor 2 fault flag up on mine, purchased a new sensor but trying to figure out which was sensor 2 - now i know!

Just for clarity you want to keep light pressure on the brake pedal so that when the sensor is removed brake fluid will be pushed out, rather than air being sucked in - is that the idea behind it?

thanks again! :thumbsup:
 
Changed a few of these sensors, slight pressure on the brake pedal as described earlier stops any air getting in when you remove the duff sensor, just have the replacement to hand so there is no delay in fitting it. On my Launch software their is an option to align the two sensors electronically in the BMW menu special functions. This just equalises their pressure readings and can be viewed in live data on the Launch Tablet.
 
thanks!....i swapped it out eaily without any pressure on the brake pedal...just unscrewed the old one and banged the new one in quickly...tiny bit of fluid loss, but nothing major...cleared the codes, went for a drive and all good :thumbsup:
 
jpvd said:
just unscrewed the old one and banged the new one in quickly...tiny bit of fluid loss, but nothing major.
Click to expand...
I was going to say that, but mentioned it a few weeks back and was mildly rebuked for assuming everyone was good with their hands.
Can you please tell them all how really simple it is. :D
 
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