Awence

Hello I have this 4500 express van that has a parking brake light that flashes for a bit and then goes away while driving the vehicle. We checked the brake fluid level, we checked for leaks, we checked the brake calipers and rotors but it all looks good. We checked and changed the sensor that goes on the brake master cylinder. The light goes off after about 10 min of driving but then goes away. Is it possible this is a cluster issue? Maybe an electrical issue or grounding issue?

mountainmanjoe

Run a full diagnostic scan with a professional tool.

RoadTrip

The scan should show you if you have problems with any of the wheel speed sensors. The warning light may be telling you you have an abs problem and a scan can check the abs module.

Awence

We have a snap on Apollo D8 and there are no codes present

mountainmanjoe

Is it supposed to scan ABS systems? I didn't see it anywhere on this page: https://www.snapon.com/EN/US/Diagnos...ucts/APOLLO-D8

Awence

Yes it scans ABS systems and it has no codes at all no abs light or check engine light. What we have found now is that the light only comes on while it is stopped in drive and applying the brake pedal and when accelerating it comes off.

mountainmanjoe

so scan it when the light comes on. I surprised it doesn't get stored in the code history

Triaged

Maybe that light is hooked up to a pressure differential valve like old school pre-ABS systems and it catching a pressure differential? Maybe it's a fluid level sensor? Maybe it's the switch on the parking brake? I'd want to know if there is an internal leak in the master cylinder.

mountainmanjoe

on a 2015?

a parking brake pedal that didn't full release is a possibility though. Make sure nothing is blocking the pedal.

Triaged

At this point it's just a line of code to make it turn on the brake light and it's possible someone put that line in? Maybe not as likely as the parking brake pedal switch but something I'd look into if my light came on.