Diagnostic System Check

Install scan tool. If scan tool powers up, go to next step. If scan tool does not power up, perform appropriate diagnostic procedure. See SELF-DIAGNOSTIC SYSTEM in appropriate BODY CONTROL MODULES article.
Turn ignition on, engine off. Following scan tool manufacturer's instructions, attempt to establish communication with Body Control Module (BCM) and Powertrain Control Module (PCM). If communication with BCM and PCM is established, go to next step. If communication with BCM and PCM is not established, diagnose communication problem with class 2 device. See SELF-DIAGNOSTIC SYSTEM in appropriate BODY CONTROL MODULES article.
Select display DTC function for BCM and PCM. Record all displayed DTCs and status of displayed DTCs. If DTCs are displayed, go to next step. If no DTCs are displayed, see SYMPTOM TESTS .
Retrieve DTCs and perform appropriate test. See DIAGNOSTIC TROUBLE CODE INDEX table.

DIAGNOSTIC TROUBLE CODE INDEX

DTC

Description

B1000, B1339 Or B1449

⁽¹⁾

Door Key Switch Unlock Circuit Low

Left Front Door Unlock Circuit Low

Left Front Door Unlock Circuit High

All Doors Unlock Circuit Low

All Doors Unlock Circuit High

All Doors Lock Circuit Low

All Doors Lock Circuit High

Door Lock/Unlock Switch Circuit Low

PXXXX

⁽²⁾

UXXXX

⁽³⁾

⁽¹⁾	See appropriate BODY CONTROL MODULES article.

⁽²⁾	For any DTC beginning with the letter "P", see appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.

⁽³⁾	For any DTC beginning with the letter "U", diagnose communication problem with class 2 device. See SELF-DIAGNOSTIC SYSTEM in appropriate BODY CONTROL MODULES article.