2001 Yaris - Wooly, non-centering power steering

[blanki1981]

Hi all!

 

I’m a new club member seeking some advice please. My wife has a 2001 Yaris 1ltr that we’ve had for about 3 years. The car was purchased from an old gent and it’s only done 18,000 miles. The car is the French built model with the electric power steering. It’s been very reliable but the steering has always been odd in that it requires constant correction and doesn’t re-centre itself at all. I’ve previously spoken to our local Toyota dealer but have been told it is normal/just an electric power steering trait. Recently I’ve had the chance to drive another mk1 Yaris and it is now more apparent that our cars steering isn’t right.

 

I’ve found several previous posts about similar issues, the resolutions included poor Battery, tyres out of shape, tracking out, worn control arm bushes, faulty p/s ecu, faulty p/s motor. Some of the posts also refer to a process called zero point calibration that the dealer can complete using their service tool, although our dealer appears not to be aware of this. Having now eliminated everything except replacing the ecu and motor, I plan to do these next.

 

My questions are:

- After replacing the ecu/motor will I need t have this zero point calibration done at a dealer or should it be pre-calibrated?

- There appears to be 2 versions of the ECU from the mk1 89650-0D020 and 89650-0D021 does anyone know if they are inter-compatible? My car has the 0D020 version.

- Are there any other things I should check prior to replacing the ECU and Motor.

 

 Any help would be much appreciated

 

Thanks

 

Ian

[Peter S]

If I were you I'd take it to a tyre specialist and get it put on a tracking computer and have a four wheel alignment check done. I don't think the electric power steering powers the steering to centre it just to assist the turning effort of the steering wheel. Both my cars have electric power steering and they don't automatically centre when the car is stationary. From my knowlege the steering geometry is responsible for the re-centering of the steering.

[blanki1981]

Hi Peter,

Thanks a lot for your reply, I'll look into getting the 4 wheel alignment done next before I start pulling the car apart. The steering on our car although light and clearly assisted, offers no resistance or correction at all which makes for a disconcerting driving experience. I'll report back if the alignment helps.

regards

[Cyker]

Don't Mk1s all have hydraulic PAS??

I thought the Mk2's was when they switched to electric PAS...?

But yeah, it is the steering geometry (Or, more specifically, the castor) that makes the steering straighten up.
However, IIRC, we have had a case in the past where the PAS was fighting the natural centring because the positioning sensor thingy whatsit was faulty.
 

[blanki1981]

Hi

Yeh I think the mk1's had both hydraulic or electric PAS based on where they manufactured, we've got a French one. I think the sensor your referring to might relate to the "zero point calibration" that's mentioned in some of the other threads I've found. I think it must be a fairly uncommon procedure due to the puzzled looks I get when I mention it to the dealer though!.

regards

[AdyP]

My daughters 53 Yaris 1.0 has the same issue.  Please let me know when you manage to identify the cause.  Thank you.