I finally broke down and bought the AutoTap Express. There's a special deal till 12/20 for $50 off. Check out
Comes out to $99 plus shipping. OBDII to USB adaptor, software and runs on a laptop (computer not included).
Oppie
Got the unit yesterday. A little odd that the engine has to be running to connect between OBDII and the laptop computer. Haven't tried key in the run position but engine not turning.
No diagnostic codes were showing but the engine was not running smoothly and the traction control had shut down. Traction control turns off when engine is not running correctly.
Found that the coolant temperature was only about 150 which is too low. This compares with a unusually low heater discharge temperature. I tend to believe the CTS and will replace the thermostat. Also saw the bank 2 short term fuel trim wildly fluctuating. This is likely a bad O2 sensor or a vacuum leak. Sure enough, I found a cracked vacuum hose. Fixed the hose, reset the ECU; engine runs better and traction control is active again.
Probably the reason that no DTCs were set is that the engine didn't get hot enough to validate the codes. Many of the codes are set only when several conditions are satisfied like the engine is at operating temperature. This avoids phantom codes that might pop up on cold start.
The AutoTap Express device only diagnoses the engine. Will not show any data for the other modules (Transmission control, body control). Haven't confirmed that it will at least display codes from other modules.
Oppie
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