Check PCS system warning

Unfortunately it's raining today and the check pcs system is on again.

 

I had this happen to me recently on my 2010 Prius with 116,400 on it.

However, I'm associating my instance of the error to using Torque Pro w/ a Plugin & the OBD2. Granted, an argument could be made that the error should have appeared earlier, but given the error disappeared after i removed the OBD2 (so that Torque wasn't running a Plugin). This is in no way scientific -- but I've since uninstalled the Fuel Economy plugin, driven 10 miles and had no issue..I'm going to re-install the OBD2 and take the car on another trip in the next 2 weeks (hopefully) and see if the error returns. If it doesn't, I'll re-install the Plugin, see if the error returns & hopefully find the cause (for me, at least).

• Feb 17th
  • Purchase @ 115,900 mileage
  • Pre-purchase inspection @ local hybrid repair shop (passed with flying colors & high remarks on the battery health)
• Feb 19th
  • fillup 87octane (~8.85gal)
• Feb 23rd
  • Toyota dealer does required Recall work on it
• March 17th
  • Install OBD2 bluetooth unit (unit is attached & affixed so it does not come off without manual intervention)
    
  • Running Torque Pro
• March 21st
  • Install 'Fuel Economy' plugin from Google Play store to work in Torque
• March 23rd
  • drive 30 miles on highway, pull into gas station
  • put in Techron additive 12oz
  • fillup 8.85gal 87octane
  • start car -- CHECK PCS
    • turn off car
    • start car -- CHECK PCS
      • turn off car
      • Remove OBD2 adapter
      • start car (and drive 330 miles) == no check engine light
• March 25th
  • drive 10 miles, no issues

 

I solved my issue. I changed out the 12v battery and I haven't had an issue since. Prior to changing the battery, I did have it tested under load and it was coming in on the low side. I don't recall the voltage but the tech told me to change the battery.

 

I had this happen and my techstream said it was the front right wheel speed sensor. But it seemed like things were going haywire when the display started flashing between "check PCS system" and "check cruise control system".

So I replaced the 12v battery (even though it still tested at 12.4V)... Nothing... must really be the sensor.
So I tried cleaning the connector even though it looked spic and span... Nothing

Then had planned to clean the connector as a last effort. It's just a couple screws and 5 or 6 (carefully removed) plastic anchors to remove the wheel well cover and I found that a damn rodent had gotten up in there and gnawed the wires off! (And scratched up this weird white maxipad looking thing at the top of the cover.)

20190920_095806 by corystal posted Sep 23, 2019 at 9:28 PM

Right at the harness too so there was barely any wire to work with

20190920_100318 by corystal posted Sep 23, 2019 at 9:28 PM

After trying unsuccessfully to dismantle the harness I decided to solder it back together... Which would not have been possible without my alligator clip wire holder thingy.

20190920_110038 by corystal posted Sep 23, 2019 at 9:28 PM

20190920_110050 by corystal posted Sep 23, 2019 at 9:28 PM

20190920_110517 by corystal posted Sep 23, 2019 at 9:28 PM

SUCCESS!!
Happy to have cruise control back

 

I had the same error on my 2010 Prius V with 78K miles. The fix for mine was to pull the speed sensors on the front and clean them with a paper towel. I also used air to blow out any debris that may have been on the inside, but I doubt that made a difference. The passenger side front sensor had brake dust on it and I'm assuming that was the problem.

I did learn a couple things that may be helpful to others:
1) I stopped by O'Reilly auto parts, but their code reader didn't have the ability to check the speed sensors. My next step before the fix was to purchase one of the blue tooth ODBII scanners. My guess is they would be more comprehensive and tell you which sensor is not working.
2) If you have to replace one of the rear sensors, I found a great youtube video on replacing the hub. Its helpful even if the hub on yours is good.

 

I have an update. The message came back on after about 45 miles. I ordered an OBD2 sensor that would read ABS codes and found there was a message ID C1391. (Abnormal leak in accumulator). Thanks to another post on this forum, I found theirs was covered under warranty. When I shared that information with the Toyota dealer, they confirmed there was an "Enhanced Warranty that is valid until this November so they are fixing it for free. Its a 10 year old car so I'm grateful they were willing to cover this and I hope its helpful to someone else.

 

I had this issue on a 2013 PIP using a generic obd2 Bluetooth device. After purchasing a Carista the issue went away.
Using the Carista OBD2 Bluetooth Adapter on my Toyota Prius -

 

Have a 2012 Toyota Prius Plug-In; got a right tire Blowout that was Bad, as soon as I pulled off the side of the Road I got a Yellow Triangle, Check PCS System, Check Cruise Control, And Traction control light. If you read other posts where this has happened; pressing PCS button, turning Traction control on or off does Nothing! Dealer said it needed new Clockspring and Spiral Cable which is one little Unit; very EASY to do yourself, A 5 year old can do, so that was Replaced, Still have all 3 lights on my Dash. If you get a Clockspring from Dealer they want about $700.00, if you get a Clockspring yourself you can find OE ones for $12.00 Bucks on Ebay with lifetime warranty. DEALER also wanted another $700.00 For Labor, it takes about 5-10 minutes to install a new Clockspring! If Everytime I get a Flat Tire I have to deal with all these lights, Clockspring gets fixed, and still have all the lights, I think this will be my last Toyota!!!!! So many people have the same exact problem; all I want is for Toyota to fix the Problem, and from what I've researched, Toyota will make you spend thousands on replacing parts, they will tell you this will fix issue, when that doesn't work, they make you spend money on other parts, this continues for awhile, I'm trying to save money, I'm going to a different dealer today, I will let you know if this Mysterious cause of the Check PCS Light/Yellow triangle/Check Cruise Control Light, and Traction Control Light Gets Solved.

 

any updates bro? I’m having the same issue and I replaced the rear Passenger wheel hub already as the dealer told me to replaced.

 

I was having this same issue with the PCS light at the top right corner, 'Check PCS System' on middle display, and the orange exclamation point on the left. This is on my 2011 Prius (5 w/ advanced tech pack).

I have had the light on for half a decade, literally, and have checked all the things mentioned in this thread and dozens of others I found online. I took it to three different dealers and have been quoted prices in the thousands of dollars multiple times to swap radar modules, replace sensors, replace the lens that is the toyota emblem, etc... I never paid the exorbitant quotes because the logic never seemed quite right for the error ('someone must have bumped your car', all kinds of other strange logic). Also, strangely, the error(s) would go away if I ever drove for a couple hours without stopping, then it would come back if I did so again. Anyway, after years and years I searched youtube for a fix today on a lark and someone posted a video two weeks ago with a simple procedure to fix this on a Prius V, I figured it was worth a try and IT WORKED.

Here is the video:

Incase that video ever gets taken down and/or someone is reading this years later this is what it said to do:
1. foot on the brake and turn the car on
2. push the button on the end of the cruise control stalk to turn cruse control on
3. push the cruise control stalk away from you (for Res) and hold for 2 seconds, then release it
4. push the cruise control stalk up three times in rapid succession.
At this point my car displayed a message on middle upper display 'adjusting radar system', it then alternated with that message and 'Check PCS System'. I waited about 30 seconds with these messages alternating and then
5. turn the car off
6. turn the car back on
Errors were all gone.

Hope this works for other people.

 

Is this for a 2nd Generation Prius?

 

Gen 3, 2011

 

Really? The video shows a Generation 2 Dash.... Unless I am miss seeing it....

 

The video is not mine, it is of a 2015 Prius V. I posted it because it was the source of the information. However, the procedure in the video worked for me in my 2011 Prius.

 

I'm not seeing that procedure in the 2010 repair manual PDF that kind of circulates, but I know that PDF is missing stuff. It shows an "adjust millimeter wave radar sensor assembly" for "when using the Techstream" ... which often means there's an alternative "when not using the Techstream" version of the procedure, but that's not in this PDF. Maybe @Elektroingenieur knows more? Maybe it appeared after 2010.

The adjustment procedure in the manual is not as casual as that video seems. It's got two pages for first making sure the car is level and the radar sensor is at its proper 0.2° upward angle (using a level on its level rack, and a screwdriver on the adjusting bolt as needed), then a page and a half for precisely placing a radar reflector, 5 meters ahead of the car and 15.7 mm to the right of center, then three pages for the adjustment process, with a screwdriver on the horizontal adjustment bolt if needed.

I don't know if the procedure shown above is essentially the "when not using the Techstream" version of this same adjustment, but if it is, and if you just casually do it, without the preparation steps and placement of an actual reflector target as the manual directs, you might now have a system that thinks it is adjusted, but how that adjustment compares to reality could be anybody's guess.

 

I had an issue with my ABS module on my 2012 Prius Plug-In and when they pulled the trouble codes, in addition to the ABS faults, there was a C1466 code indicating a right rear speed sensor fault. After the ABS module was replaced things were fine, but shortly afterwards the PCS warning light came on... but then it disappeared. So, I just continued to drive the car and it seemed fine.

However, after several weeks the PCS warning light came back on again, and persisted. Pressing the PCS button a few times didn't do anything, and the 12 V battery seemed fine. (The service menu stated the battery was 11.8 to 12.0 V depending upon when it was measured, but when I measured the leads with a voltmeter recently, it was actually 12.45 V.)

My local mechanic looked at the codes again but he did NOT detect the right rear speed sensor fault. Instead, he found a left rear speed sensor fault. Interestingly, he was able to get the fault to go away simply by tapping on the left rear wheel hub, and the PCS warning light would go away too. However, despite the fact he was able to make the warning light turn off intermittently, he recommended replacing both wheel hub assemblies, because he said my bearings were humming. (The wheel hub assembly includes the hub, bearings, and speed sensor.) I got both the right and left replaced, and now the PCS warning light has stayed off.

This issue started happening around the 127000 km / 79000 mile mark. This is a shorter life span for wheel bearings than I previously might have expected, but I don't have a garage so my car stays outside all the time in Canadian weather and my wheel bearings would see harsher wear than many others. OTOH, my wife's 2016 RAV4 hybrid has a bit higher mileage and also stays outside, but so far the wheel bearings have held up.

 

hmmmm.. interesting!