Brake Recall Service Done - Unsure if working properly

[Shivering Timbers]

We live in Colorado and sometimes have slippery conditions in the winter. We had previously experienced a slight interruption when braking on ice (this happened twice in late January), so when the braking software recall was announced, I took our 2010 Gen III Prius to the local dealership on Feb 12 2010 and had the software flash performed. It did not take long. Since then, we have not experienced the same problem, so we think it did make an improvement with that particular problem. However, it appears to have caused a greater problem.

Last night, we had snow on ice, and very slippery conditions. Just to try it out, I went to a deserted roadway near our home and tried to stop a number of times, at speeds from 15mph to 40mph. I could not get the ABS system to come on at all. At least, I don't believe it was coming on, because the ABS light would not come on, and there was none of the pulsating sound or feeling we used to have when the ABS worked. Under these conditions, I tried all different braking pressures, and as soon as I applied moderate or harder pressure, all four wheels locked up, and I would slide to a stop in the same manner as older cars without ABS used to do. This is OK on a deserted road, but not in normal driving conditions.

Now, I am an older guy, and I learned how to drive on ice and snow long before ABS was invented, so I can live without it, now that I know I don't have it. But I do think it is deceptive or just plain stupid that Toyota would fix an ABS problem by simply deactivating it, which is what the software "fix" appears to have done, at least for our Prius.

I encourage anyone who has had the recall "fix" performed, to check and see whether or not they still have the ABS system they paid for when they bought the car.

Other info: the ABS light does come on when starting the car, so the light is not burned out. We bought our Prius in August 2009, and it has less than 6,000 miles on it. Thanks.

[thbjr]

Well, since it rained last night and wet streets are as slick as it gets here in Phoenix, I took our Blue Prius for a rather aggressive spin around the block. I accelerated to 30-35 MPH and slammed the brakes. No ABS light on the dash, but definite ABS brake reaction. The standard chirping or grinding as the brakes released and re-engaged. I repeated the test 6 times, all with the same good results.
We had the ABS ECU flashed last week on the Blue and I'll be getting it done on the White car this week.
Sounds sort of like the OP got a bad flash download. I think it would be prudent to return the car to the service department for repair.

[Paradox]

There is no ABS light which lights up when the ABS is activating during a hard braking situation.

[guinness_fr]

Braking on snow can be very deceptive, I'd suggest testing the ABS on dry concrete, you'll definitely be able to tell whether ABS engaged or not (continuous screeching noise).

[32kcolors]

That's real clever of Toyota. Instead of eliminating the transition between regen and ABS, they just got rid of ABS altogether...

Being sarcastic of course!

[spiderman]

Did the car stay straight or did it slide sideways? Were you able to maintain steering control while braking?

[tumbleweed]

Thanks for the post Shivering.

Anytime software (or hardware) is changed there is the potential of unforeseen problems. I hope you can repeat your test and let us know the results. Where I live I don't think there will be anymore snow this year so I will have to test mine on paved and gravel roads.

[Shivering Timbers]

We had more time (and daylight) this morning, so we took our Prius back out to the lonely, snowy road and gave the ABS some more test-runs. The very good news: the ABS works! I was wrong in my original post, and I apologize for the misinformation.

The not-so-great news is that the ABS light no longer works, when braking with ABS. This confirms the post by Paradox, elsewhere in this string. However, I can live with that, although it is rather irksome.

From our skid-marks in the snow, and from the pulsating, ratcheting sound inside the car, we could see that the wheels were definitely alternately locking then releasing, just as they should under ABS. However, try as we might, even essentially standing on the brakes, the slip-indicator light absolutely would not come on. (The slip-indicator light serves as ABS, VSC, and TRAC indicator light, according to the manual. It did come on, as it should, when we accelerated hard enough to spin the front wheels in the snow).

The slip-light used to come on under ABS braking, before we got the Toyota software "fix". Now it does not. Therefore, it appears the "fix" did not deactivate the ABS, as I earlier believed, but it has deactivated the light, at least for us. I wonder if others have experienced this.

Replying to Spiderman: the car did not swerve, while using ABS in our slippery conditions. It stopped straight. It did seem to me that it took significantly longer and further to stop, than other ABS-equipped vehicles we have had in the past. However, that is just an opinion, which I cannot back up by actual test in this case. Thanks.

[Paradox]

The not-so-great news is that the ABS light no longer works, when braking with ABS. This confirms the post by Paradox, elsewhere in this string. However, I can live with that, although it is rather irksome.

I have never owned a car that had a light light up when the ABS was activating during a braking situation. There are ABS lights which light up when there is a system malfunction, but that is all I have ever had in any of my vehicles.

If the car is stopping adequately, I'd just enjoy the car and not worry about which lights are and are not lighting up lol. That's just me.

[Shivering Timbers]

Whoops - I went back and re-read Paradox's post. I'm sorry and must apologize again. I see now that he was saying that there is not supposed to be a light, when the ABS is doing its thing. I had misunderstood his post.

I went back and re-read the manual, and I see that he is correct. I had thought that the slip-light had illuminated when we used ABS in the past, but I must be mistaken. Therefore, I had no reason to complain about the light not coming on, and I apologize for my original post. As far as I know, now, the Toyota "fix" has solved the problem.

Sorry for the false alarm folks. We can all go back to loving our Prius'es now.