GM Service Manual Online
For 1990-2009 cars only

Important: DO NOT replace the body control module (BCM) unless a diagnostic trouble code (DTC) remains current after all the DTC tables have been executed. DO NOT replace the BCM based on history codes.

The BCM has the following characteristics:

   • Connected to the Class 2 serial data link
   • Capable of setting DTCs
A history DTC code is a fault that disappears in the next ignition cycle. The history DTC codes are useful in diagnosing an intermittent problem. An explanation of these DTCs is given in the following table:

Diagnostic Trouble Code

Explanation

Automatic Light Control

  • B2575

DTC B2575 Headlamp Request/Feedback Mismatch

  • B2577

DTC B2577 Headlamp Control Circuit Low

  • B2578

DTC B2578 Headlamp Relay Output Short to Battery

  • B2585

DTC B2585 Parklamp Control Circuit Malfunction

  • B2587

DTC B2587 Parklamp Relay Output Short to Ground/Op

  • B2588

DTC B2588 Parklamp Relay Output Short to Battery

  • B2647

DTC B2647 Ambient Light Sensor Circuit Low

  • B2648

DTC B2648 Ambient Light Sensor Circuit High

Class 2 Serial Data

  • U1000

DTC U1000 Class 2 Serial Data Link Malfunction

  • U1016

DTC U1016 Loss of Communications with PCM

  • U1040

DTC U1040 Loss of Class 2 Communications with ABS

  • U1096

DTC U1096 Loss of Communications with IPC

  • U1176

DTC U1176 Loss of Communications with RFA

Controller Memory

  • B1001

DTC B1001 Option Configuration Error

Daytime Running Lamps

  • B2600

DTC B2600 Daytime Running Lamp Circuit Malfunction

  • B2601

DTC B2601 DRL Stuck

  • B2602

DTC B2602 DRL Relay Output Short to Ground/Open

  • B2603

DTC B2603 DRL Relay Output Short to Battery

Doors

  • B3127

DTC B3127 Driver Door Unlock Output Short to GND

  • B3128

DTC B3128 Driver Door Unlock Output Short to BATT

  • B3132

DTC B3132 All Door Unlock Circuit Low

  • B3133

DTC B3133 All Door Unlock Circuit High

  • B3137

DTC B3137 All Door Lock Circuit Low

  • B3138

DTC B3138 All Door Lock Circuit High

Foglamps

  • B2532

DTC B2532 Front Foglamp Relay Out Short to Ground/Open

  • B2533

DTC B2533 Front Foglamp Relay Output Short to Bat

Inputs

  • B2965

DTC B2965 Key In Ignition Fault

  • B1369

DTC B1369 Ignition 0 Fault

  • B1374

DTC B1374 Ignition 1 Fault

  • B1379

DTC B1379 Ignition 3 Fault

Interior Lighting Control

  • B2558

DTC B2558 Interior Lamp Control Output Short to Battery

Panic Horn

  • B2752

DTC B2752 Horn Relay Coil Circuit Low

  • B2753

DTC B2753 Horn Relay Coil Circuit High

Passlock® Theft Deterrent

Refer to Theft Deterrent System

  • B2947

DTC B2947 Security System Sensor Power CKT Low

  • B2948

DTC B2948 Security System Sensor Power CKT High

  • B2957

DTC B2957 Security System Sensor Data Circuit Low

  • B2958

DTC B2958 Security System Sensor Data Circuit High

  • B2960

DTC B2960 Invalid Coded Key Present

  • B3031

DTC B3031 Key Decoder Device in Assem Learn Mode

  • B3033

DTC B3033 Security System Indicates Tamper

Rear Compartment Lid Release

  • B3267

DTC B3267 Decklid Output Relay Short to GND/Open

  • B3268

DTC B3268 Decklid Output Relay Short to BATT