Wondering if others here have had a similar issue to me. A few months ago I bought a salvage LS460 to repair (quite minor damage to FL guard and bumper) and have it inspected and registered. The repairs are done and everything was fine except the other day I removed the steering wheel to center it before it went in for a wheel alignment (that part went fine).

I now have a VGRS fault code C1591 Actuator Neutral Position Calibration Undone. I do use Techstream. Not a great idea to remove the wheel - I know that now. I also have an account with AlldataDIY and the procedure to solve this code is to drive straight above a certain speed for more than 5 seconds. I've tried a few times with no luck. Using the live data in Techstream - I'm supposed to have a 'VALID' flag for a particular parameter (STRAIGHT ANGLE) before the code will clear. No luck solving this. I do see the steering angle change realtime on the data stream however there are two inputs in the live data but only one is input changing. I double checked the clockspring and steering sensor and everything looks OK.

In a last ditch effort - I disconnected battery for a while but no luck. Steering has defaulted to 3.2Turns mode (lock to lock) when in park where as it should be in 2.7 turns mode when stationary or at at low speed.

The main dash warning light is on with a VGRS issue on the dash. I have tried a few things, with one being a zero point calibration on the steering sensor but this fails due to the C1591 code. This code must be cleared first so I'm stuck in a loop.

Any thoughts? I'm booked in for it's final inspection next week but this will fail due to the MIL showing. Thanks.

 

Perform VGRS system calibration .

 

I found this through google.
https://static.nhtsa.gov/odi/tsbs/20...61747-2273.pdf

 

Thanks for that. Just to clarify on the VGRS system calibration - do mean in a test drive or in software? When I'm in Techstream under the VGRS menu there are two options that seem useful - signal check and to do sensor calibration. Both tests get nearly through all the way but come up with an error at the end saying DTCs detected and to fix that problem first. I have the C1591 code (Actuator Neutral Position Calibration Undone) in that VGRS steering ECU which I'm assuming is causing the issue. I did test drive the car as per the procedure I found online for VGRS initialization however I've since found an expanded procedure which mentions to stop (after going straight) and to do a full lock to lock which is what I didn't do atthe time so I'll try that when I'm home next week. I just found the a LS460 specific proecdure as a TSB on Alldata. I have the INVALID result under the STRAIGH ANG FLG parameter currently.

1. Drive the vehicle on a straight road at 22 mph(35 km/h) or more for 5 seconds or longer. At this point, the steering wheel will still remain off--center by 5--10 degrees.
NOTE:In this step, the neutral position of the steering wheel is recorded in the VGRS ECU memory.
2. Perform normal cornering 2--3 times. The steering wheel position is automatically corrected in this step.
3. With the vehicle at a standstill, turn the steering wheel from lock to lock, then drive straight again, and the steering wheel should be centered.
4. Confirm the steering wheel is centered.
- If the steering wheel is centered, initialization is complete. Go to step 5.
- If the steering wheel is off-center, go to step 1.
5. Confirm initialization has been completed.
A. Access the VGRS Data List using the Lexus Diagnostic Tester.
B. Confirm the "STRAIGH ANG FLG" parameter reads "VALID."
NOTE:Prior to initialization, the "STRAIGH ANG FLG" parameter will read "INVALID".
When the VGRS initialization procedure is complete, the "STRAIGH ANG FLG" parameter will change to "VALID".
- If "VALID" and steering is off--center, refer to ETAS 2007 model year LS 460 Repair Manual: Steering Column: Variable Gear Ratio Steering: Calibration.
- If "INVALID", return to step 1 and perform driving procedure again.
- If "INVALID" returns again, check for VGRS system DTCs and diagnose the condition following the procedures found in the Repair Manual.


I also have a couple of other codes in other ECU's. Airconditioning low pressure (had the condensor out for a while and am booked in for a regas nextweek) so this shouldn't affect it but I do have a a fault with the parking assist ECU as well so I wonder if this has any affect (is this the code that stops the above VGRS procedure) as the parking assist would use steering angle input and drives the steering rack for parking. The front parking sensors were triggering randomly and in the wrong order and then the front sensors stopped working altogethor all so I've got a secondhand ECU coming to solve that.

 

Yep that's the one I found but have since realized that I missed step 3 on my test drive. Will need to redo.

 

I thought that you should at least try it with the extra steps to see if anything changes. I've had my Steering wheel off a number of times recently and never had a problem clearing the codes with Techstream.

 

I'll give it a go when I'm back home next week and report back. I've taken some screenshots of Techstream which I'll post too - hoping to show a before and after. It would be great if the correct test drive is the only requirement.

 

As an update to my original post - I couldn't somehow get the calibration to work by doing the straight drive and turning the steering wheel left to right as per the procedure. I had techstream connected whilst driving and pulling over to check things but no go. The STRAIGHT ANGLE flag was always 'invalid' and I couldn't get it to be valid so the C1591 code wouldn't clear which is needed first before it would allow the VGRS calibration procedure to be performed.

I've since bougth a secondhand steering ECU from Yahoo Auctions in Japan. It's mounted under the glove box and easy to access. Bolted it in and all good now - no more codes. ECU was only 30 bucks and about the same for postage.

Cheap fix in the end.

 

Thanks for checking back in with the final fix.

 

can you tell me the location of this Ecu please ?

 



 

any parts numbers or pics ?

 

Considering your location, it’s best to go to a part seller website and enter your VIN.