Brake warning light 2001 sienna

[johnfin]

My brake warning light stays on for long periods in the morning. The fluid is at the correct level. Any ideas?

[sl2eggplant]

I'm sure the Sienna brake system and sensors are similar to most other cars on the road.


This at least one brake fluid sensor in or near the brake master cylinder. For the Sienna it might be hard to find since the master cylinder is tucked away but if you look at another car, you should see a wire or two going the master cylinder / reservoir.

You may have air in the master cylinder which is triggering the sensor. The only other location that a sensor can be "sensibly" located is the ABS pump unit, but I think that would trigger the ABS warning light.

I would check your fuses since it requires little to no effort.

If fuses are okay, I would bet that you have some air in and around your reservoir / master cylinder or the sensor is broken (unlikely though). How's the brake pedal. Is it squishy? Note, that a firm brake pedal can still have air in the brake line. Best thing would be to bleed the brakes which is a considerable task in itself.

[johnfin]

How hard is it to blead the brakes on a ABS system?

[sl2eggplant]

Almost forgot, you should check your parking brake. Obviously, when you set the parking brake, the brake warning light comes on. Its a long shot, but if the parking brake switch is broken or acts up, then that will trigger the brake warning light.


Moving on ....

Bleeding ABS and regular brakes is done the same way. The only time you need to worry is if say you took out a brake caliper and didn't plug the end of the brake line, then the brake fluid would leak out eventually leaking from your ABS unit as well. Thats when you have trouble because you will need a special tool to force the abs unit to actuate so you can bleed the air out.

If your system is sealed and has a little air somewhere in the master cylinder / reservoir, you can bleed that out similar to a regular brakes since the ABS unit does not actuate, the brake fluid and air pocket should flow right through.

I would recommend that you exhaust all options before bleeding the brakes since you only want to "break" open the brake system when you have to change calipers / wheel cylinders or change fluid.

[chuckoff]

Two things turn on the "brake" light. The parking brake warning switch, and the low fluid level float in the master cylinder level. So, the fluid is low, the float is stuck, or the parking brake indicator switch is malfuncitoning. The ABS system does not turn on that light.