Weak 12v Battery = Cannot Complete Alignment

This was a new one for me, and is a heads-up to all of you since this can happen.

I took the 06 Prius that I had been working on to a local tire shop for an alignment. After the alignment was completed, it was necessary to perform a zero-point calibration, which I am sure we are already aware of. The Hunter Alignment Consoles are now able to handle this through their Codelink attachment, which is a unit that plugs into the vehicle's OBDII port.

So, the alignment tech plugged in the Codelink and allowed the software to check the systems and begin the calibration process. Almost immediately, we get a "low battery voltage" message and the process was unable to continue. We tried again and again, but received the same result-- the Hunter software simply would not allow us to proceed with a low battery voltage. I had already suspected 12v battery issues with this Prius due to very low MPG and slow engine starts, so this incident only confirmed that suspicion.

Luckily, this was a full-service shop so the mechanic in the next bay brought over his Snap-On Verus. The mechanic was not familiar with Toyotas, but once we entered the Wheel Alignment Menu the software gave us the option to perform a steering torque sensor calibration. At the time, we were not sure if that was the same thing as a zero-point calibration, but I later found out through my shop foreman contact that it was. The calibration was successful, and the steering feel is now much, much better.

The lesson learned from this incident was that if your 12v battery is very weak, the Hunter Winalign Software will not be able to perform the necessary steering torque sensor calibration. It is likely a safeguard to prevent issues in case the 12v battery dies during the calibration process, which can result in fried computers. Also, if the alignment shop had not been a full-service repair shop, they would not have the fancy Snap-On Verus Scanner and would have been unable to complete the alignment. The shop said that if the scanner was not able to perform the zero-point calibration and I had to bring the vehicle back with the new battery installed, they would have charged me to perform the calibration. This is because the weak 12v battery was not their fault, so please beware of this.

Hope this helps.

 

I don't know if that would have been possible since the vehicle was already raised and the heads were attached to the wheels. The shop either did not have a portable jump starter or was not interested in putting in that much effort.

 

After the alignment and steering torque sensor calibration, the steering feel is significantly heavier.

Any thoughts on why this is happening? I have a few theories but I am curious as to what you guys have to say.