The cam phasing system is a hydraulically actuated phase shifting
mechanism. The powertrain control module (PCM) supplies the ignition
positive driver and ground circuits. A pulse width modulated (PWM) driver
controls the amount that the camshaft actuator solenoid assembly
advances or retards the exhaust camshaft. The exhaust camshaft is
commanded to a maximum retard position of 25 degrees. When the exhaust
camshaft is retarded at the maximum rate, the duty cycle of the signal is at
100 percent. The maximum advance rate has a 0 percent duty cycle. Other
than when the camshaft is at full advance, a 50 percent duty cycle is used
to maintain a steady retard angle.

The driver has the ability to detect an electrical malfunction in the ignition
positive or ground circuit. If an electrical malfunction occurs, the driver
signals the PCM to set this diagnostic trouble code (DTC).

A common code that can be set is p0014 or p0016 on Chevy Trailblazer,
GMC Envoy, and Oldsmobile Bravada.
A few related questions and answers
2006 chevy tailblazer code p0014 and stalls out at stops or idle.
2002 trailblazer 4.2 l straight 6 cyl code p0016 adjustable cam timing.
Cam timing phaser solenoid valve system