Control module

Hello, I’m Pete from the Car Genius team at RepairPal. I’m sorry you’re dealing with this concern on your 2006 Toyota Solara. Based on the information provided it is unlikely that the removal or replacement of the stereo in your vehicle is causing the concerns you are experiencing. With what is described many of the concerns you are witnessing could be caused by a low voltage concern due to a weak, failing alternator, a weak, failing vehicle battery, loose or corroded battery cables or connections or other wiring concerns causing a loss of voltage. The battery tell tale light will usually come on anytime the vehicles computers detect a low voltage concern, and as you load up on pulling power from the battery by turning on accessories or other components in many cases this can cause some problems with how the vehicle operates as your vehicle is designed to operate on a bare minimum or 12 volts DC. Anytime your voltage drops below this you might start seeing transmission shifting or operational concerns or other various electrical or engine operational concerns. There may also be a second concern here with how your transmission is operating. I recommend having your vehicle battery, alternator, cables and connections checked/tested to see if any concerns are found. If an issue is found it will need to be resolved. Then operate the vehicle to see if the transmission concern still occurs. If the transmission concern still occurs then it would be best to have your transmission tested/inspected to pinpoint the cause so it can then be repaired properly. Internal solenoid or sensor failures or even internal mechanical issues can cause transmission shifting and operational concerns. If you need assistance connecting with one of our RepairPal Certified shops, more advice, or have any further questions about your vehicle, we’re here to help. Just give us a call at 877-913-1554 where we will be happy to assist!