Check PCS system issue and solution

I have had my current 2010 Prius hatch V for about 6 years now, the car has been mostly worry free till early this year. The issue started coming up as " Check PCS system", this would happen mostly when I would press the brake peddle while the Dynamic radar cruise control would be on. After that you cant use the radar cruise control unless you turn the Cruise control off and back on again.


The issue somewhat disappeared when the weather started being nice again, so through the summer it was somewhat ok with occasional warning here and there, till earlier this month. The same warning would come back on and eventually it started giving me the yellow triangle along with PCS, Brake, ABS, TCS warning etc. The whole dash would light up like a Christmas tree, how fitting this time of the year.

The dash would reset itself eventually and or if I shut the car and turned it back on. The lights indicated an issue with the ABS system but more worryingly I'd loose brake booster pressure. The car would turn into an old 60s classic with no brake booster pressure, scary as you'd never know when you'd go from regular brakes to boostless brakes, if thats a word.

No check engine light by the way, this would happen very randomly, only thing that would be common every time would be bad weather.

I hooked up a snap on fancy scanner from a buddy of mine and went digging in the ABS system, following are codes that I got, at first I thought it was the speed sensor but during a live data run all sensors were reading fine so I didnt think that was an issue, unfortunately I should have done the test on the highway as thats when the whole issue would usually come up.

I did some research and thought the worst that the Prius might need a new brake booster/pump. As most recently the ABS started kicking in without any need of it on dry tarmac.

I limped the car into the local Toyota dealership, paid the diagnostic fee and braced myself for the worst.

After the diagnostic they recommended a new left rear wheel bearing/hub as its got the speed/ABS sensor built right into it along with the cable as the contacts were corroded due to age/salt etc. Along with that a new set of front rotors/pads were also recommended. Quote was around $1000 for the hub/wire and $500 for the front brakes.

I gladly paid them the $129 diagnostic fee, bough the parts through my commercial account with them, spend 8 hours yesterday and installed everything. I ended up changing both rear hubs/wires as when I did the scan there were speed sensor codes from both sides in the history.

Most of the time was spent fighting with the hubs as the corrosion over the years havent been kind to them and the car. I had to macgyver the whole thing and use an old HD bearing puller without the jaws to leverage the hub off of the chassis.

Drove the car 50 miles since the install and everything is copacetic.

So if you have a check PCS warning or ABS warning I'd advise on checking if the speed sensors are working fine and if they have any codes. Unlike most cars the speed/abs sensors are part of the hub hence the hub has to be replaced in order to replace a faulty sensor. The pins on the connectors to and from the sensor are really tiny and are open to the elements. Its not a question of if they'd every go bad, its a question of when, especially if you live in the rust belt areas. I'd highly advise on investing in a good scan tool as well, especially if you do your own work. I am on the hunt for one now as I can always borrow my friends snap on but I'd rather have something in my arsenal as well for diagnostics.

By the way the car has 282k miles on the odometer.

 

I guess my excitement was short lived, the stupid "check cruise control" warning is still coming on when ever I press the brake peddle while the cruise control is turned on. The brake booster/tcs/pcs issue is all sorted though, now I have to go digging again to see if I can rectify this cruise control issue.

The cruise control works fine, both the adaptive and conventional cruise, its only in adaptive mode that every now and then if the cruise control is on (on but not set) and I press the brake peddle it shows the "check cruise control" warning. Turning off the cruise control and turning it back on resets it and lets you use the cruise control again.

Looking at the screenshot of the fault codes from a week ago, I wonder if the C1241 code is pertaining to this matter, I am going to hook up the snap on tool to the car again later and see go fishing for a code with it.


Here is a short video of the issue, dont mind the dirty dash