GM Programming Tips

[Klaus]

Technicians continue to report occasional problems with incomplete programming events or errors. This leads to damaged controllers and unnecessarily high warranty. Here are tips that may help prevent some of these problems.

Insufficient Battery Voltage -- The proper battery voltage is critical to programming. If voltage drops too low at the end of the programming event, calibration files or VIN data may not be written, causing problems or failure.

Be sure the battery is fully charged before starting the programming. If the battery voltage is questionable, you can use a Midtronics PSC charger during programming (July 2005 TechLink). At this time, GM has not validated any other charger for this purpose.

Not Turning Accessories Off -- Before programming, turn off all electrical devices, such as headlights, radio, HVAC, etc. And during the programming event, do not turn on any electrical devices.

Not Using Current Software -- You must use the most current Tech 2 software release and the most current TIS software release. To be sure you are always using the latest data, you must update your Techline terminal as soon as you receive the new software.

Not Waiting -- Before performing a programming event, you must turn the ignition key on. Do not begin programming right away. It’s critical to wait until all modules on the vehicle have “awakened” before beginning. (This is the same principle as waiting for any computer to “boot up”. You cannot start to access applications on your PC until it fully boots up. The same applies for any vehicle systems with multiple modules.)

If you try too soon, you will get a No Communication message on the Tech 2. A good rule of thumb is to observe the instrument panel lights and tones. When everything stops, you can safely proceed. Plug in your Tech 2 (and CANdi module if required).

Not Cycling Ignition -- When working on a GMLAN system, you must cycle the ignition off and back on after programming each module. Do not begin programming a second module without turning the ignition off and on.

TIP: During the ignition OFF time, avoid opening and closing the doors for 30 seconds until the controller can write the new values.

Voltage Held in Components -- Some components contain capacitors, which can store voltage after being turned off. If stored voltage is released by a module while you programming another module, it could cause confusion on the data bus, causing U codes to set. To prevent this, you may be instructed to disconnect the battery cables and touch them together. This drains the stored voltage from capacitors.

Using the Wrong Tech 2 Adapter -- There are three 16-pin adapters that have been used with the Tech 2. At a glance, they all look the same (fig. 8).

Do not use adapter p/n 71419.

You can use either of the adapters numbered GM 3000098. They have been manufactured by two different vendors. One of them is coded VTX 02002955, and the other is coded HP 5063-3255. Either of these will work with CANdi modules.

http://www.gmtechlink.com/images/iss.../TLaug05e.html