Service Brake System error?

JIMMYPAGE

MEMBER
2002 OLDSMOBILE BRAVADA
4.2L
6 CYL
4WD
AUTOMATIC
257,000 MILES

I am getting an intermittent “Servive Brake System” error

Sometime s this error comes on right when I start up the car, sometimes it comes on after driving and sometimes it doesn’t come on at all.

I notice when it’s on, I don’t have ABS or All-wheel drive, but brake work just fine.

When it’s off, my ABS works like normal.

The emergency brake cable is not hooked up.

I’ve replaced the all-wheel drive module several times. Sometimes it works, some times it doesn’t.

When I get new tires or have the tires rotated, I just go to the cheap local place.

It’s their a sensor that’s not hooked up? Could it be a fuse? Anything else I should check?

Thanks.

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Wednesday, December 31st, 2025 AT 7:51 AM

1 Reply

STEVE W.

MECHANIC
15,355 POSTS

When the light comes on with that message it means the brake system shows an error. Because the ABS, traction control and AWD all use the same parts of the brake system any fault in it will also turn those off. The first thing to do is scan the truck for codes, when the light is on it stores codes related to the systems. With those codes you have a starting point to find the problem, that is because it could be a bad wheel speed sensor, a bad ABS module, even low brake fluid can cause an error, but looking at the codes will give you a clue where to look. If you don't have a scan tool that can read ABS codes many parts stores will scan the vehicle, but they may not scan the ABS system, depends on store policy. Get the code(s) and post them and we can track down the problem together.

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Wednesday, December 31st, 2025 AT 9:39 AM