Last post on Oct 13, 2012 at 2:43 AM
You are in the Lexus RX 400h
What is this discussion about?
Lexus RX 400h, Steering, Suspension, Hybrid Cars, SUV
#2 of 31 Electric Steering
Jul 06, 2005 (1:15 pm)
Does anyone know whether the steering design on the 400h is a "full Steering by wire" or is it just partial??
The implication is that partial-electric steering design still allows you to steer when you have no electric power. In other words, the steering shaft is still mechanically connected to the wheels.
#3 of 31 Re: Electric Steering [maxamigo]
by PFFlyer@Edmunds HOST
Jul 13, 2005 (3:49 pm)
The 2006 RX 400h is listed as having "Power Rack and Pinion Variable Assisted Steering " which sounds like it's NOT 100% by wire.
#4 of 31 Re: Electric Steering [pf_flyer]
Jul 14, 2005 (3:20 am)
That, is comforting!
#5 of 31 Re: Electric Steering [maxamigo]
Feb 14, 2006 (9:18 am)
the steering system on a rx400h uses a electric power assist. the steering wheel is still attached directly to the rack and pinnion.
#6 of 31 Steering Problems Update
Jul 08, 2005 (8:58 am)
Just had my 400h alignment fixed (See original post below). The Tech drove around with me for 15 minutes to try to see the issue for himself -- he was very interested in analyzing any issues with the new 400h systems. He agreed the car wandered a bit on irregular surfaces, but felt the new electric assist (vs hydraulic) might explain some of the feel. He supervised the realignment and corrected a minor "toe-in" issue that might explain some of the wandering symptoms. He did emphasize minor...
After driving about 45 miles on the re-aligned car, there is a clear improvement. The car is still somewhat sensitive to a consistent road camber, but the "loose steering" feel is gone. It feels more solidly centered, and does not follow minor surface changes as aggressively as it did. In short, it feels like a more "solid" steering system than before.
As an aside, I had a 330 as a loaner car. The hydraulic assist was clearly storinger than the 400h electric, but I'd say the overall steering feel was pretty close to my realigned 400h. The other interesting thing was that the 400h feels MUCH more powerful -- the instantaneous electric torgue really makes a big differnce in standing starts, and passing situations!
"After driving about 600 miles in my new 400h (27.5 mpg), I've decided there actually is a bit of a steering issue with the 400h. At first, I thought my alignment was off due to extreme pulling to the left on my main commute road. The road is crowned heavily, with drainage to the left. I have to hold the wheel fairly firmly to keep it going straight. Now, switching to the other lane, which drains right, I get a fairly strong pull to the right. I've driven this road for years, and have never noticed this problem with my 540i, Audi Allroad, or Explorer. The Explorer drives like a heavy truck, but doesn't pull like the 400h on the same road.
I then went out and drove on a number of flat local roads, and I'm convinced the alignment is OK. In a parking lot,for example, I can release the wheel and the car will go dead straight without any noticeable pull.
My conclusion is that the 400h steering system is "different". It feels like the electric boost or "centering power" is unsufficient at highway speed, or stated another way, that the front end is overly-sensitive to camber in the road. I noticed that letting go of the wheel on a slightly pitched road, even at very low speed, results in a fairly rapid turn -- more so than any of my other cars.
The effect does feel like misalignment to me, but it occurs in both directions depending on road camber.
In the end, I've decided it's a bit annoying, but certainly not a driveability or safety issue. I just feel like I notice small differences in road camber much more. When driving on windy roads, I notice nothing at all. On cambered straight roads, I feel the effect almost constantly... "
#7 of 31 Re: Steering Problems Update [shelt]
Aug 01, 2005 (1:21 pm)
I, too, had steering problems with my 400h. I found that when I hit about 45-50 mph, there was a point where the resistance to steer to the left increased - it was like someone else was holding on to the steering wheel. After overcoming the initial resistance, things returned to normal, but there was a definite spot in the steering where things weren't "right". I took the car into my Lexus dealer and they determined it was a failure in the "power steering rack". They replaced the "power steering gear assembly", the "electric link assembly", and performed a four wheel alignment. Now the car steers and feels as it should and I couldn't be happier. btw - I had a brand new 330 loaner - what a difference in performance between it and the 400h.
#8 of 31 Power Steering Computer Failure
Jul 13, 2005 (10:59 am)
I just received word that the RX 400h in our long-term fleet is in the shop. The Power Steering Computer failed. The vehicle has less than 3,000 miles on it. It needs a new computer which is on backorder at the dealer. The vehicle will be in the shop for at least a week.
#9 of 31 Re: Power Steering Computer Failure [Sylvia]
Jul 22, 2005 (7:37 am)
Was the dealer able to resolve this problem and get the vehicle back on the road again???
#10 of 31 Re: Power Steering Computer Failure [horns1976]
Jul 26, 2005 (6:40 pm)
I don't know but we should be able to read about it in the next long-term update on the vehicle when it is published. If I venture down to editorial I'll be sure and ask.