Hi all, my car has decided to give me a new challenge. It’s not the typical parking brake issue I’ve had before. This time the parking brake doesn’t seem to be engaged but the car is constantly chiming saying parking brake on. Here’s my troubleshooting steps so far.

Tried actuating the parking brake on/off. Car says cannot apply parking brake.
disconnected Battery cable to reset system then ran jumper wires to parking brake module plug to ensure parking brake was released. The motor does operate this way.
followed prompts to reset parking brake (hold foot brake, etc)
car continues to warning chime constantly when moving.

oddly the BRAKE light on the dash is activated when I push down the parking brake button. The opposite of what I expect.

I shut off the car and tried playing with it a bit more with just key on. I don’t hear any parking brake motor noises when toggling the parking brake and car says cannot apply parking brake.

im left wondering if there’s a bad sensor somewhere or if the parking brake really is not fully disengaging.

 

After some further diagnostics I think the sensor is correct. After taking a short drive. Left rear rotor is quite hot compared to the other side so the parking brake must be dragging. I once again ran the jumper wire and confirmed that the cables did loosen on both sides. Knowing that this issue is just going to come back I’m wondering about disconnecting the cable from the brake caliper or something along those lines to get me going again.

 

After removing battery cables did you touch them together to drain system?

 

Yes indeed. Touched battery cables together.

After further efforts I think I arrived at a temporary solution. I’m thinking my module has gone bad.

So simply using the jumper wires to manually release the parking brake didn’t satisfy the “parking brake on” chime and warning message. I decided to once again disconnect the battery and reset. But this time I popped the wheels off and removed the linkage from the calipers while it was loose. This created a new issue when I got back in the car. It wanted me to go through the foot brake/parking brake calibration procedure. I was hoping I outsmarted the system and got it to move the cables without implicating the brakes but it was too smart for that and didn’t register the calibration. This led to the same chiming situation as before just with a different warning message. So the final effort was to unplug both plugs from the module. Seems to also have the side effect of disabling cruise control but at least the car is driving with no constant chiming. Not a real fix but something to allow me to use the car without losing my mind haha.

 

the parking brake module monitors current. go scan for dtcs

cable puller motor waits for a current increase from the mechanical resistance of the brake assembly and it expects it in a certain timeframe

 

If you allow the parking brake to retract the cables while they are disconnected, they will probably over-travel and kill the actuator.. Ask me how I know. 04 XJR. I removed the parking brake calipers and ran for years with the light in the dash. Won't pass inspection in some states.......