Description & Operation

WARNING: This page is about a different car, the 2002 Oldsmobile Bravada, 2002 GMC Envoy XL, 2002 GMC Envoy, and 2002 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.

WARNING: Vehicles are equipped with air bag supplemental restraint system. Before attempting any repairs involving steering column, instrument panel or related components, see DISABLING & ACTIVATING AIR BAG SYSTEM in AIR BAG RESTRAINT SYSTEMS article in RESTRAINTS.

CAUTION: When battery is disconnected, vehicle computer and memory systems may lose memory data. Driveability problems may exist until computer systems have completed a relearn cycle. See COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION before disconnecting battery.

AD-244 generators are non-repairable. They are electrically similar to earlier models. Generator features the following major components:

A delta stator.
Rectifier bridge.
Rotor with slip rings and brushes.
Conventional pulley.
Dual internal fans.
Voltage regulator.
Pulley and fan cool slip ring and frame.

The AD stands for air-cooled dual internal fan; the 2 is an electrical design designator; the 44 denotes the outside diameter of the stator laminations in millimeters, over 100 millimeters. The generator is rated at 150 amperes. The generator features permanently lubricated bearings. Service should only include the tightening of mounting components. Otherwise, the generator is replaced as a complete unit.

Voltage regulator controls field current of rotor in order to limit system voltage. Regulator switches current on and off at a rate of 400 cycles per second in order to perform these following functions:

Radio noise control.
Obtain correct average current needed for proper system voltage control.

At high speeds, on-time may be 10 percent with off-time at 90 percent. At low speeds, on-time may be 90 percent and off-time 10 percent.

The IPC illuminates the battery indicator when the following occurs:

The PCM detects that the generator output is less than 11 volts or greater than 16 volts. The IPC receives a class 2 message from the PCM requesting illumination.
The IPC determines that the system voltage is less than 11 volts or greater than 16 volts. The IPC receives a class 2 message from the Body Control Module (BCM) indicating the system voltage.
The IPC performs the displays test at the start of each ignition cycle. The indicator illuminates for approximately 3 seconds.
The ignition is on, with the engine off.

The IPC illuminates the battery not charging indicator in the driver information center when the following occurs:

PCM detects that the generator output is less than 11 volts or greater than 16 volts. The IPC receives a class 2 message from the PCM requesting illumination.
The IPC determines that the system voltage is less than 11 volts or greater than 16 volts. The IPC receives a class 2 message from the BCM indicating the system voltage.