Conditions for Setting the DTC

WARNING: This page is about a different car, the 2010 GMC Sierra and 2010 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.

The system tests the lock solenoid circuits by checking for unwanted voltage.
The underhood fuse block supplies B+ on the battery positive voltage circuit and reads the voltage back on the lock solenoid control circuit.
If the TCCM detects a low voltage return when a high voltage is expected, or a high voltage return when a low voltage is expected, the DTC is logged.
The fault must remain current for 1 second to set the DTC.