Conditions for Setting the DTC

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2007 GMC Yukon XL, 2007 GMC Yukon, 2007 Chevrolet Tahoe, 2007 Chevrolet Suburban, and 2007 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.

During the key ON test, the ECM detects high voltage on the generator turn on signal circuit for at least 5 seconds.
During the RUN test, the ECM detects low voltage on the generator turn on signal circuit for at least 15 seconds.