ABS and brake light on

[loriandan]

Hello all. New to this forum and Mazda ownership. I just bought a 2003 Protege5. The ABS and brake lights are on and I am unable to read codes through the ABS diagnostic port. I believe the ABS module / computer is faulty. I am having trouble locating the part through the search of various parts suppliers. Has anyone run into this problem and could you help me out with the part # ?
Thanks in advance , Dan

 

[tweety2300]

Abs diagnostic port? Go to autozone they should be able to pull a code from the ecu

 

[loriandan]

Abs

The ABS system has it's own diagnostic port near the firewall behind the battery. The ECU is not sending any codes and when hooking up to the ABS port it wont communicate with the scanner.

 

[iJay]

It wont send n e codes from there unless you are using the Mazda tool. OBDII reader will be ur friend. And if the ABS and brake light are on chances are its a bad rear abs sensor, they are finicky when they age simple to change just take ur time. Check the diagnostic port below the dash it will give you ALL error codes for the car.

 

[cutchemist]

I know the last time mine came on, the screw on the sensor to the hub loosened. I doubt thats your problem though.

 

[kamesama980]

Autozone won't scan ABS codes AFAIK unless you have a really proficient one near you with a non-company provided scan tool.

Since both lights are on, check your base brake system first. If the red brake light comes on, ABS is disabled which causes the ABS light to turn on. an ABS problem usually lights the ABS light but not the red brake light. This would also corroborate with not having any ABS codes... it's not an ABS problem

 

[wedgeindy]

It's mostly likely a fluid problem, which seems to come from worn pads....I've found my P5 eats pads bad..maybe it's a canadian winter thing, but if I have pad/rotors last 40K kms (25K miles) I'm a lucky guy...esp the rears..dang they wear fast.
If your ABS fuse goes the ABS and brake light go on....I'd check that too.

 

[loriandan]

Hello all. After getting nowhere troubleshooting with Alldata's schematics and swapping out the ABS unit, I checked the sensors with a meter and found a faulty rear wheel speed sensor.( Like iJay said ) Why this should turn both lights on I don't know. Also it doesn't send any codes to the OBDII. All's well that ends well.

 

[stkmp5]

I had this problem and it was the 2 rear abs sensors we bad. I used the underhood diagnostic port and grounded one of the terminals to flash the light on the dash and get the codes.