Monepit -You're absolutely correct. Anytime a sensor (potentiometer) is replaced, a Tech 2 is required to download it's operating parameters to the Folding Top Control module.
Shop manuals are a must with this car if you want to dig into it. It's a shame that the Tech 2 is so expensive; running a diagnostic with it is one of the first steps in many of the troubleshooting procedures found in the shop manuals.
CC
CC
There are good (being a relative term) deals to be had on eBay for Tech 2 scan tools, but I had to be patient and check the listings regularly for about two months. I paid $2200 for a brand-new GM Tech 2 with CANdi module, pre-loaded memory card (works on 2010 models) with all necessary cables and connectors including a nice polyethelyne storage case.
The amount of information it will display is staggering for an automobile. If you're having an issue with a door switch for example, you need only press it and watch the screen to see if it indicates the switch changes state. You can cycle individual Folding Top solenoids, run graphic tests on the HUD; the list goes on and on. It even checks the fob signal staus.
The first step after connecting and powering it up is entering what type of vehicle you're testing. Once identified, you can run a full diagnostic in about three minutes. If a fault code is identified, you can concentrate on that particular subsystem without having to start over and perform redundant tests. Very similar to the way I ran diagnostics on Trident submarine weapons systems. The XLR differs from my CTS-V in that I can run just one comprehensive test to check out the car. I would imagine GM would standardize this methodology on newer models.
For me, it was a good decision to acquire a Tech 2 since I enjoy figuring out how the systems work and fix them when possible. The shop manuals are pretty thorough, but there is still supplemental info (akin to tribal knowledge) available to dealers that isn't included. Bruce is a good source for some of the more useful info.
CC
Thanks Bruce! Noted, remembered, stored. Other than clearing DTCs (or waiting 50 ignition cycles) only a shop manual, tools, sensors/switches are required. I note that with a value range of 0-250 counts for the sensors, the measured range may be 35-202 counts (Folding Top Position Switch, for example.) All sensors being created equal, will a replacement duplicate the 35-202 full range? How much slack is there before the FTC loses track of expected position and halts operation. I know it tries to continue to drive the mechanism to the reference counts stored in the FTC memory but what will make it stop (time out) and issue a TOP NOT SECURE messsage?
Correct me if I'm wrong, but after re-reading the manual as I understand it, the Open and Closed reference parameters are re-learned after each successful top operation.
