Keyless Entry System: Overview Chevrolet Silverado 2500

Test Description

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

1. 2) - Lack of communication may be due to a partial malfunction of the class 2 serial data circuit or due to a total malfunction of the class 2 serial data circuit. The specified procedure will determine the particular conditions.
2. 5) - The presence of DTCs which begin with "U" indicate some other module is not communicating. The specified procedure will compile all the available information before tests are performed.

Scheme 1

Scheme 2

The number below refers to the step number on the diagnostic table.

1. 3) - This step checks the keyless entry serial data circuit for voltage supplied by the body control module (BCM).

Symptoms - Keyless Entry

Important: The following steps must be completed before using the symptom tables.

1. Perform «Diagnostic System Check - Remote Keyless Entry»(ref-176703-S40410799552005051200000) before using the Symptom Tables in order to verify that all of the following are true. There are no DTCs set. The control module(s) can communicate via the serial data link
2. Review the system operation in order to familiarize yourself with the system functions. Refer to «Keyless Entry System Description & Operation»(ref-176703-S15043449712005051200000) .

The number below refers to the step number on the diagnostic table.

1. 17) - An illuminated test lamp at step 17 reveal a short to voltage in the serial data circuit.

Scheme 3

Scheme 4

Scheme 5

Unlock All Doors (Second Operation)

Press the UNLOCK button a second time within 3 seconds of the first press in order to perform the following functions

1. Unlock all doors.
2. Flash the parking lamps twice.