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Home >> Pontiac >> 2001 >> Aztek Base, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 710 (Lighting Systems) >> Diagnostic Information and Procedures >> DTC B2647: Ambient Light Sensor Signal Reference Circuit Open Or Shorted >> Test Description
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Test Description

WARNING: This page is about a different car, the 2002 Chevrolet Malibu. However, it is still accessible from the selected car via links, so may be relevant.

The numbers below refer to the step numbers on the diagnostic table.

  1. 2.  The normal operating voltage of the ambient light sensor (photocell) is 0.5-4.5 volts.
  2. 3.  If the value is above 0.5 volts, with the sensor disconnected, a short to voltage exists. If the value is below 0.5 volts, a short to ground exists.
Fig 1: DTC B2647
G01779596Courtesy of GENERAL MOTORS CORP.