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Diagnostic Trouble Code Definitions

WARNING: This page is about a different car, the 2003 GMC Sierra, 2003 GMC Cab & Chassis Sierra, 2003 Chevrolet Silverado, and 2003 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
DIAGNOSTIC TROUBLE CODE DEFINITIONS

DTC (1) Description
B1327  Battery/Source Voltage
B1328  Device Power Circuit High
P0562  Low System Voltage
P0563  High System Voltage
P0615  Improper Voltage Level On The Output Circuit That Controls The Starter Relay
P0621  High Generator Turn On Signal
P0622 (Gasoline Engine)  Improper Pulse Width Modulated Signal
P0622 (Diesel Engine)  Improper Pulse Width Modulated Signal
P1637  Generator Turn-On Signal Circuit Voltage Out Of Range
P1638  Pulse Width Modulation Signal Out Of Range
(1) Codes listed in this table are only for testing covered in this article. For complete DTC listing, see appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.