My ABS system is spontaneously triggering the breaks when making a left turn, especially a left U-turn, or even when going through a left hand curve on the highway exit ramp. Once it happened when trying to turn into the center lane to safely make a left turn. There might have been some small gravel on the ground in some of these instances, but the reaction seems like a false positive for a skid, as if a tire started slipping. BACKGROUND: The car is a 2010 Prius, about 192k miles, has no error codes, and no warning lights on. We replaced the hybrid battery with a refurbished one in August, replaced the tire pressure sensors in September, and had the rotors cleaned in October. The car has 3 newer tires around 9/32 and 10/32 (front driver, and back two), and 1 older tire at 4/32 tread depth (front passenger). We pumped the older pressure up to 40 PSI to see if that would help, but it did not. The previous owner is a friend and says the car was never in any accidents. He also said he occasionally experienced the same problem. Toyota ran a diagnostic and did not know what is causing the problem, but suggested replacing the ABS brake booster pump actuator and thought that was “probably” the issue, but they just seemed to give us a laundry list of potential repairs and could not actually diagnose the problem with certainty. I do know the car has the original actuator and is beyond replacing under warranty. We took it to a recommended hybrid mechanic for a second opinion and they said they do not think it’s the actuator, they think the actuator is fine. They thought perhaps the calipers needed to be cleaned and that this might be interfering with the ABS sensors, thus triggering the issue, but that did not work. Now they think it might be the steering angle sensor because they have seen that cause this issue before, even when there were no codes to indicate the sensor was bad. However, when we asked, they also thought the difference in tread depth between the front passenger tire and the rest of the tires could also trigger that issue. Overall, it’s been to 3 mechanics and they have said it’s in immaculate condition otherwise. Any help would be greatly appreciated! We live in Florida and want to make sure the ABS system will operate safely in a downpour!
Getting on road of similar conditions with Toyoda scanner w freeze frame duplicate issue gravel on road etc make it happen and view freeze data it should be the VSC engaging not ness the ABS. But they all comm on same bus or such. Sherwood at Royalty automotive in Fla comes to mind
The difference in the tires is probably the problem. Try rotating the tires from front to rear and take a test drive with many U-turns.
If they are all the same tire size you should be okay whether one tire is bald and has no tread left shouldn't really make a difference and shouldn't activate the skid control or the other funny business like if you had a 195 tire and all the rest were 185 the rest of the numbers being the same I've had this happen a couple of times trying this theory out it works flawlessly I'm not sure that a few 30 seconds of tread would be enough to make this engage because of the tire size difference that would literally be hundredths avengers or something what I think it takes a little more than that but yeah give it a whirl I guess and see if that makes a difference hell put some real tires on the car and see if that's straightens it out I don't think so.
