ABS C0205/32 Troubleshooting

First post after lurking on this page for 12 years. I'll apologize in advance for the length, but I wanted to provide all the details

Vehicle: Single owner 2008 Prius. 72k miles and very reliable up until now. Located in WNY so it does have a significant amount of rust underneath.

About a month ago my ECB (!), ABS and VSC lights came on while changing lanes on the highway. I started researching similar issues on PriusChat and decided to buy a cheap OBD off Amazon (Veepeak OBD II Scanner) that has proven to be worthless. I checked the lights and found ECB 41, ECB 42, ECB 44, ABS 36 and the other "hey look at X" codes.

I decided to take the car to a local dealer to have some recalls taken care of and have them do a diagnostics ($180). Their finding was:

• Replacement of B1S1 O2 sensor
• Replacement of axle - boot dislodged and no grease in CV joint
• Fluid leak from transaxle unit
• Front wheel bearing replacement - Noise during test drive
• Front speed sensors - debris on tip of sensor
• New tires and alignment - last winter on my snow tires and will be replaced in spring
• Noted significant rust underneath vehicle

To me, the key here was the debris on the ABS (speed) sensor. So I cleaned them both, but the lights came back. Shortly after that my speedometer went to 0 while test driving and stayed at 0. So I replaced both front ABS sensors and reset the codes. The lights came back on, but now I only had ABS 32 (C0205/32 - Left front wheel speed sensor signal malfunction).

Upon inspection I realized I had installed the left sensor incorrectly.I tried fixing it to no avail and found a cut in the cable. So I replaced the front LH sensor again and cleaned the tone ring as best I could (had thick dirt between the teeth). I ensured all tires were at the proper pressure and reset the codes again by jumping the OBD pins and pumping the brakes 8 times. The ECB (!), ABS and VSC lights continue to come on about a quarter mile into the test drive and I continue to receive an ABS 32 error code.

I just checked the front LH ABS sensor again and everything seems to be in place. I read a couple mv AC when spinning the wheel and the sensor reads 1.526K ohms. I'm not sure what the resistance should be, but this seems to be in the normal range?

Both sensors were 'you get what you pay for' eBay purchases. The car is old and I should start thinking about replacing it, but I would like to get a little more out of it if possible. Any recommendations would be much appreciated. Thanks in advance!

 

The car drives fine until the lights come on. Then the brakes and control do feel different. Sometimes traction control would kick on when braking and the car got down to about 10mph.

My annual inspection was due about two weeks after the issue began. Since it's now expired I've only driven the car as-needed for test drives.

 

PriusCamper - I do all my own work within reason. I just decided it was worth $180 for the dealership to figure it out for me. I've also never brought it in for recalls, so two birds one stone

SM-G965U ?

 

Now that you mention it, there was 'crud' built up under the sensor mounting point that I removed on the RH side. I'll give it a shot on the LH to see if that helps.

I hand spun the rotor while cleaning the tone ring. No cracks or anything else unusual.

 

Well I'll be damned There was a small amount of white corrosion where the sensor bolt goes in. I think it's from the metal ring in the original sensor. It was maybe a mm thick...I cleaned it up and reinstalled the sensor and was able to drive for 15 minutes or so without any issues. I'll drive the car for a couple days and report back. Thanks!

 

No more issues with the ABS sensor. Thanks @mr_guy_mann!