Conditions for Setting the DTC

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2011 GMC Yukon XL, 2011 GMC Yukon, 2011 Chevrolet Tahoe, 2011 Chevrolet Suburban, and 2011 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.

P0667

The difference between the transmission fluid temperature (TFT) and TCM substrate temperature is greater than 20-50°C (36-90°F), depending on the average of the TFT, TCM substrate and TCM power up temperatures.
The difference between the TCM power up temperature and TCM substrate temperature is greater than 8-10°C (14-18°F) depending on the average of the TFT, TCM substrate and TCM power up temperature.
The above conditions have to be met for 5 minutes.

P0668

The TCM internal temperature is -249°C (-416°F) or less for 1 minute.

P0669

The TCM internal temperature is 249°C (480°F) or greater for 1 minute.