drchris6000

Ok so I've been dealing with this problem for two years with no solution. The ABS, TCS, and E-brake lights come on every time I drive more than 5 minutes. It seems to depend on how warm the car is but it comes on everytime, sometimes sooner. I brought it to dealer and they said it was the Power Steering Module. Swapped it out, no change. The tried a few other things and said I should change my brakes. Changed my brakes and no change. I've had my buddy run the code multiple times and it seems to be saying it's a brake pressure sensor. Question is how do I find one and where is it located for me to change? I've been looking on this forum and seems a few people have had this problem but no one mentioned the brake pressure sensor so maybe there is another issue and the OBD is just using that code. Help!

ASH8

There is no "Brake Pressure Sensor" in the RX-8 which is sold as a separate Part.

Can you list the DT Code??

These are the Parts which could possibly be the issue.

ABS Unit (part with all Brake Pipings going into it).
Wheel Speed Sensor for ABS (one on each wheel)...total of 4.
Brake Vacuum Booster (possibly) unit behind Brake Master Cylinder.
Brake Master Cylinder (possibly), unit that take brake fluid.
Front Wheel Hub (where front sensor installs)... (possibly)

ASH8

Couple of other things...

Is your Brake Fluid Full??..in reservoir??

Is you car battery in good condition??

Would then look at Wiring Connections to those parts above which have an electrical connection.

You MAY need to have your DSC (TC) and Yaw Rate Sensor re-initialised which means the Dealer to do so with their WDS Software...particularly if most of the electrical parts above have been removed or replaced.

Cam

iTrader: (1)

I can tell you the brake pressure sensor is an internal part of the ABS unit in an Audi/VW and the ABS unit must be replaced if defective.

most likely the same for Mazdas

ASH8

Yes I agree, that is why I put the ABS unit first, there is no other external Sensor for brake pressure, so it has to be the ABS unit..if this is the issue.

Would like to know the DTC.

drchris6000

I'm thinking back to when I first noticed the issue and the only thing that coincides with it was I had my wheels refinished, so they were removed and put back on.

I recently put a new battery in and cleaned all the connections.

All 4 rotors and pads are new, so the wheels have been off again.

The ABS sensors all looked in good shape, I didn't change any of them.

My brake fluid is full and I had it tested, says it's ok although I've never changed it.

I'll run the code again and update the thread.

Thanks for the help.

jrx13

My gf's Mazda3 had a brake pressure sensor fault. We had to replace the ABS Hydraulic Unit/Control Module. Like the others said, it's not a serviceable item from Mazda.

There were some UK parts place opening up the Mazda3 ABS units & replacing the sensor as a reman but I couldn't find any in the US. Luckily, Mazda covered it under goodwill warranty even though the car was out of warranty by a few months. The car had very low mileage.

The workshop manual was very specific in the Mazda3. You cleared the code and if the same code came back (brake pressure sensor fault), replaced the unit. No other diagnosis needed.

I'm pretty sure the RX-8 one will be similar. Maybe you can find a used one?

drchris6000

The code that came up was C1290, not sure if that helps.

ASH8

•
C1290
■
The pressure from the brake fluid pressure sensor when not braking exceeds specification.

POSSIBLE CAUSES•
Open or short circuit in the wiring harness between DSC HU/CM terminal B and brake fluid pressure sensor terminal B

•
Open or short circuit in the wiring harness between DSC HU/CM terminal C and brake fluid pressure sensor terminal C

•
Open circuit in the wiring harness between DSC HU/CM terminal E and brake fluid pressure sensor terminal A

•
Malfunction in the brake fluid pressure sensor

•
Poor connection at connectors (female terminal)

•
Open circuit in the wiring harness between brake light noise filter and brake switch

•
Open circuit in the wiring harness between brake light noise filter and DSC HU/CM

•
Open circuit in the wiring harness between brake light noise filter and STOP 15 A fuse

•
Brake switch malfunction

•
STOP 15 A fuse malfunction

•
Brake light noise filter malfunction



Looks like ABS unit to me...

drchris6000

So if it is the ABS unit I'm assuming it needs to be swapped, is the dealer the only place to get this item or should I look into salvage yards as well?

ASH8

well over $1000 for a new one at a Dealer??!!

Easy_E1

iTrader: (2)

I would go ahead and check the electrical just to eliminate any possibilities of it being related to the issue.
But it'd be funny if it was just a fuse.