The LS460's automatic parking brake was not working since I bought the car. On inspection before I bought it I saw that there was some past water accumulation in the trunk and saw the residue on the parking brake ECU. When I hooked up my computer to the car and did a scan it showed no communication to the Parking Brake ECU. On opening up the ECU I could see corrosion etc which definitely showed signs of water damage. So worst case scenario I thought I needed a new ECU which can be found online for under $200 so ordered one after I bought the car. When the new ECU came in I swapped it out and did a reset memory and linear valve offset calibration on the ABS/VSC/TRC module and cleared the DTC. No error message on the dash yet but it takes a bit for everything to register at times. Next day I was driving and the same error message started coming up intermittently which was weird. I noticed that the colder it got the longer the error message would stay on and then it would go away for awhile. The parking braes would work though, if I switched the parking brakes on it would actuate and engage and when I switch it off I could hear it disengage. I went ahead and took the trunk apart again to look at the parking brake module again, the module looked fine but when I inspected the plug it showed signs of corrosion.
I took pictures for reference and then depinned the wires from the plug which revealed the problem. One of the plugs had a lot of corrosion and was barely making a connection. Once depinned the end pretty much fell off because it was that corroded.
This kinda made sense to why temperature would affect the connectivity. Took some measurements on what pin to order to get this connected back up again, also went ahead and measured the power and ground plug as well just in case it needed it, for future reference.
Ordered the right pins, cleaned up the plug and sprayed all the connectors down with electronic contact cleaner a thin coating of dielectric grease and put everything back together.
It's been a couple of weeks since this was done and no more error messages.
- AJ Abraham