Check PCS System, C1658

Recently my 2010 Prius IV had the "Check PCS System" pop up. I lost my Regen braking, DRCC, Traction Control, got the Red (!), Yellow (!), /!\, and PSC flashing, No Check Hybrid System.

I was driving to work and it popped up along the way, I'm in Canada so It's been particularly cold out lately (-20C)

5min down the road, everything cleared and the car returned to normal. I used the Secret Diagnostic (Info/phone+lights on and off x 3) menu on the NAV to see if I could pull any codes and it gave me C1658 - Wheel speed sensor malfunction. The fault has been intermittent as I drive and aside from losing traction control and regen braking the car operates normally. no leaking of fluid or loss of brake pressure. no erratic behaviour or fluid loss.

I have a friend that gave me access to his ALLDATA account to look it up as I don't have a scanner that could pull the code from the OBD2 port. It says that one of the front two abs sensors is bad and to check them. I've ordered replacement sensors for both as I don't intend to pull the wheel all apart to check/clean the sensors and not replace them. It's cold, the job will be awful and I'm not going to pay shop rate to do it for me.

Given the symptoms and the code, I Figure I have a buildup of Ice/rust/crap or the cold weather has cause the sensor/connectors to be making poor contact due to corrosion / contraction. My OCC gets dumped every week from all the moisture buildup so ice accumulation is not outside the realm of possibilities.


I'll post a follow up with the results after I've changed the sensors out so that anyone else that has this problem/code will be able to start off with something other than a trip to a dealer/mechanic.

 

I finally got around to getting this diagnosed and repaired.

The problem went away after a few days and then didn't bother me for several months, creeping up again for a few days in the summer then disappearing again. This winter the problem reappeared and this time it didn't go away, forcing me to spend some quality time with the car and figure it out.

Initially I used the NAV system and checked in the diagnostics menu to find the C1658. This resulted in finding that I had a problem with the Advanced parking guidance system. I used alldata to figure out what the problem system was and this lead me to checking and replacing the two front wheel abs speed sensors. This didn't resolve the problem, I would get all the same symptoms erratically. I purchased a Veepeak OBD2 ELM327 reader and checked for codes. This did not produce any results as the codes that were displaying were not related to the engine which was a relief but also frustrating. A new symptom appeared which I just happened to notice because i was driving with the radio off one day, while riding the brakes and pulling up to a stop light I could hear the traction control/abs system engaging on dry pavement as if the car was sensing wheel slip. this only happened when the fault wasn't triggering. usually after feeling and hearing that the check pcs system would flash, the regen braking would shut off and the peddle would be harder to push but firm while braking.

The next method I used because I didn't have any form of techstream available or abs reader was to try using the obd2 pin jumper method. I jumped the Pins 4 and 13 with a piece of wire and was able to pull code 33 from the ABS lights flashing. VSC also gave me 43 and 45 but nothing that would lead to the brake accumulator problem that many have. Code 33 through my research lead me to replacing the rear right wheel hub assembly as it contains the sensor. After I got that finished the problem went away and the vehicle drove normally again.

I've noticed many people have had issues with the PCS system as it covers a lot of components, DRCC, abs sensors, skid ECU, accumulators among other things. For me I was fortunate in that the problem was just a wheel sensor.

Tips for others that are faced with this problem is to do the following:
If you get an ABS or check pcs system display on your MFD wait till the problem is active and stop the vehicle in a safe location.

try scanning with the bluetooth elm327 reader for codes. this will help isolate if the problem is exclusive to the ABS computers or not.
use a jumper across pins 4 and 13 to get the blinks codes and get a idea what the problems are if you don't have access to techstream or an abs code reader.

If the codes aren't active while you're trying to check it, this will create more headaches then it solves. dealerships, normal mechanics and backyard mechanics need symptoms to chase. dealers are lazy and will just replace parts at your expense. I'm cheap, i need my car, i'll learn to fix it if it will be cheaper to do myself.

To others facing ABS and Check PCS system problems. I hope this helps you in your struggles because it's been educational for me.