prime steering not going back to center

I've had electric power steering in a VW that was excellent, centered very nicely. So Toyota could make his right if they wanted to...

 

I have a 2017 Toyota Tacoma. Guess what? It's steering doesn't go back to center either.

 

so i recently acquired my 2nd 2018 prime. the first one is pretty straight and feels stable on the highway etc. the 2nd one felt a bit darty, not able to keep straight, something felt off. and the steering wheel was tilted to the right by 1-2 inches.i got the selling dealer to do an alignment for free as they agreed it should be straight coming off the dealer lot. it had 169 miles when i bought it and 424 when i brought it in for alignment a week later. well, specs were a bit off on the initial check and slightly better after they tuned it. of course they didnt fix teh wheel being off center the first time around, so i had to sit there for another hour after the alignment was done wheel is still a slight bit tilted but i'll get it done when i get new tires. you can see my alignment sheet below. any experts feel free to chime in. does anyone have official specs from toyota? there is super tiny print on the sheet that provides a range, but its pretty wide ranges...trying to attach a file with large enough resolution to capture the ranges.

 

untitled.pdf can zoom in to see specs...

 

The front doesn't look like it was that far out by looking at the new numbers.

My 2016 is hard to keep going down the road in a straight line, it takes constant correction and I have heard of others having the same issues. My tires seem to be wearing fine though. I know caster has a lot to do with it.

 

I hope someone is still listening to this post. I have a 2018 Prius Prime Plug In and I am so happy to find someone else that is having the same problem and that I am not crazy after all. There is a definite problem. Most of my driving is in town and I don't notice it as much but it is a real problem with highway driving, I drive a hundred miles and I am tired because of the constant corrections. I am going to go back to the dealer and try again. The mechanic that rode with me did not drive the car but was very polite and concerned but could not find a problem. Hopefully someone has found a solution by now.

 

There's nothing wrong with it. It's supposed to work as-described and, personally, I VASTLY prefer this approach to the aggressive wheel centering of other cars, including my wife's Mazda5.

 

If the alignment is corrected and dead on, it must be the tires. Not every tires are created equal, that is why they provide warranty not just for thread life but QA as well.

One of my previous car I bought 4 brand new tires and had nightmare issues like everyone stated in here. Did all the stuffs mentioned in this thread, long story short... it ended up a faulty rubber.

Just a thought

 

From Lex's .pdf:
Front camber: -.9° to +.6°
Caster: 6.4° to 7.9°
Toe-in: -0.3° to +.15° (really surprised to see a toe-out negative value here)

Rear camber: -1.9° to -.4°
Toe-in: +.21° to +.03°

Definitions:
Camber is the lean in or out of the wheels. Negative is lean-in.
Caster is the inclination of the steering axis. It is always tipped back. Higher gives more centering effect, but probably not adjustable. Other adjustments effect the caster reading.
Toe-in is the directions the tires aim when the car is going straight. We want slight toe-in.
Steer Ahead shows the tolerance in tire straight ahead vs. steering wheel straight ahead.
Thrust angle is the angle the rear tires are aiming. This is mainly useful for a non-adjustable rear wheel drive so the fronts can be adjusted to match. It can show crash damage or an assembly defect.

I want my car's alignment to be in the center of each of the spec ranges. Just "in spec" may be a horrible alignment if one side is at the max allowable positive and the other side at the max allowable negative, or some similar situation.

 

I will be gone before my tires are in need of replacement. However I had a 2005 Prius that exhibited some of these same symptoms and I was considering trading it in when it needed tires but I decided to put on a set of Michelins and it was like driving a completely different car so it was either the tires or the alignment or a combination of both. I drove it five more years before I traded for the 2018 Prius Prime. I like the car but just wish I could get the steering problems solved. Sometime it just seems that the steering is too tight which leads to over correction as well as not returning to a straight line.

 

I've been reading these threads since I got the prime. I've changed the pressures, and I've had dealer do an alignment. I've even test drove another prime from a different dealer and it too had the high speed lack of straight line lock problem. One curious thing I've read is someone that had 2 Prii, one of them had very light steering and tracked straight, another had very tight steering and had this issue.

 

I remember some 'stiction' that had the bad effect of missing the straight path steering so the car seemed to gently rock back and forth. Once I realized what was going on, my steering inputs changed enough it was no longer as severe. I never tried to find a technical solution as I'd already been looking at my Prius-exit strategy: (1) BMW i3-REx, and; (2) Tesla Model 3.

Bob Wilson