No, no reason to recalibrate. Just making minor toe changes shouldn't affect steering protocols in my mind. We just used the manual relearn procedure to relearn steering angle position and reset steering wheel straight ahead. Toe adjustments affect the distance relationship from wheel to wheel as well as the relationship of rack position to steering wheel. With the DAS cars you are setting the relationship from wheel to wheel with the standard manual adjustments (tie rod ends) and then using the relearn procedure to reset steering angle sensor to zero and force car to recalibrate so steering wheel is level and tires point straight a head.
It is nice that there is a manual relearn that doesn't require hooking up to a computer. Like I said, hopefully someone like Steve or another engineer can shed light on possible issues with this work flow. As of now, car drives perfect. This TSB applies to cars with off center steering wheels so logic would suggest that this is exactly what it is designed to correct.
Mike
Hey Mike,
A minor adjustment to total toe shouldn't change much in my mind either. Unfortunately I have to disagree with your original statement. According to the shop manual the alignment procedure for DAST equipped vehicles has a long list of cautions before the procedure the first one reads:
Always perform DAST calibration with CONSULT when adjusting the toe-in. (It cannot be adjusted without CONSULT.)
I see and agree with your logic RE: adjusting the toe should trigger the computer to relearn it's new position. That may be the case in the not so distant future but according the 2014 manual that is not how they want us (everyone) to perform alignments on these cars. Their theory behind this is you cannot prove (to their standards) that the steering wheel is perfectly centered enough to line the car to it. The DAST calibration procedure has you raise the wheels on the rack, perform the calibration, then set the alignment without moving the car. Logically it makes sense, practicality is another story.
I am sure someone out there will (and apparently has already) test the book's statements. I would not stake my reputation on trying to do this myself without the strongly recommended computer reset. Exceeding the allowable (and unknown) margin of error
will result in serious faults and driveability problems. There is an entire section of the book dedicated to fixing this exact type of problem.
I try to be on top of all available service procedures for these cars. It is possible you have something I have not seen. If you have something stating something to the contrary could you PM me. I am very curious there is a steering angle sensor adjustment that should be possible but nothing to reset the DAST learned positions.
The TSB for force learning a new center is something the car actually does all the time on all the time while driving...complicating matters when you are actually trying to find TDC.
I would not stake my reputation on a guess at this point. Due to the significant potential consequences for getting this wrong I would strongly urge against winging it. I am sure someone will create a thread about a problem in the future and it will attract all types of drama here but we are all learning as we go here. My hope is that enough people come across these threads and educate themselves before it happens instead of after.
