When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Hello @Linescreamer ,
It would help if you could post a picture of exactly which warning lights are illuminated, the word "BRAKE" , or a symbol with the "P" ?
On the dash info panel it says "Electronic Parking Brake Failure". The same panel that would say Jack Mode if you put the car in Jack Mode
Then I would say that you have a fault with either sides electric brake motors, or possibly the parking brake switch, or the parking brake module itself, what year, and do you have a scan ?
Then I would say that you have a fault with either sides electric brake motors, or possibly the parking brake switch, or the parking brake module itself, what year, and do you have a scan ?
Most likely a failed PB motor.
Johnny
How would I troubleshoot that? Is it obvious if the motors are working? 2013 GTC
Last edited by Linescreamer; 09-21-2021 at 12:42 PM.
You could clear the fault codes, go for a ride, and or activate the parking brake and see if the fault returns, but what I would do is, do the output tests to check the function of each rear electric caliper with your VCDS, there is also a reading for each caliper as to the current draw while operating test, that will show if either has a fault.
Yes, it would be obvious if they are working, as you can hear them when you apply the parking brake, BUT, it best to have two people, one to pull the PB switch, the other to take turns listening to each side separately, as it is impossible to tell from the drivers seat if both are working, this is of course by just using the pb switch in the vehicle, with RT VCDS you only need yourself as you can activate them separately in output test.
Johnny
Last edited by Johnny Hotspur GT; 09-22-2021 at 09:15 AM.
Thanks Johnny! I have been looking through the VCDS menus for that test. That system is not very intuitive. Is there a Bentley specific resource to operate the VCDS? Like.....ho do I know if my system UDS or non UDS? What numbers do I put in to test the left vs right side PB motors? I guess I can experiment but that probably isn't the safest way to use that tool.
I did clear the codes. It didn't go away until I drove it a few times.
Last edited by Linescreamer; 09-22-2021 at 10:44 AM.
I did a bit more troubleshooting. The motors both sound like they are working. There didn't appear to be any way to run the rear brake cylinders separately. I did the function test which opens and closes both rear cylinders 3 times. Johnny, you mentioned that the read out would help in the diagnosis. The pictures below were taken during the test. I don't see how these results can be interpreted. The left side clearly has lower readings than the right electric parking brake cylinder. What should I make of these results? Fyi....the codes were cleared, the parking brakes operate and hold the vehicle in place, however, the error message (dash lights "electronic parking brake failure ") comes back every time the electric parking brake Is used and codes are again thrown.
Last edited by Linescreamer; 09-30-2021 at 01:10 PM.
@Linescreamer ,
Yeah that measuring block group 10 is confusing, I will search as to why the difference in readings from left to right, or call Ross-Tech themselves and ask for clarification.
Below are some pictures of my readings of measuring block group 3, you can see the slight variation of amperage between left and right.
My vehicle is made up of 2006-7 brake electronics, ABS, EPB module, so I am not sure as to any differences to your 2013.
If the message returns after clearing the Intermittent fault, then please post a picture of the exact message in the Instrument cluster.
My instrument cluster shows as the last picture does when accessing the Parking Brake module with RT VCDS.
No apology necessary. Just trying to figure this stuff out. Your VCDS screen formats are different then mine. I didn't see a screen for measuring blocks which seem to display shut off current and operating counters for each left and right motors. Do you know what the -21 means from your operating function test screen? All this is Greek to me. I didn't realize that we can call Ross tech for help interpreting these readouts? I think my switch is throwing these faults but not sure. I hate replacing parts and am more of a diagnostic type. Once we understand how these work, it is much more cost effective then replacing parts.
09-15-2021 | 04:20 PM
