Diagnostic System Check

WARNING: This page is about a different variant/trim than selected.

CAUTION: Do not replace Passlock(tm) module unless there are no PCM/VCM DTCs and a current Passlock(tm) module DTC exists after system check and DTC test has been completed. Do not replace Passlock(tm) module based on history DTCs.

CAUTION: Always remove Brown connector first and install Brown connector last on BCM.

NOTE: System tests are written specifically for General Motor's Tech 2 scan tool. A generic scan tool may not be capable of performing all necessary test functions.

Connect scan tool. Turn ignition switch to RUN position, engine off. Attempt to communicate with BCM and Instrument Panel Cluster (IPC). If scan tool communicates with BCM and IPC, go to next step. If scan tool does not communicate with BCM and IPC, diagnose and repair communication problem. See appropriate BODY CONTROL MODULES article.
Check BCM for DTCs. If no DTCs exist, go to next step. If DTCs exist, go to step 4 .
Momentarily turn ignition switch to START position, do not start engine. Release ignition switch to RUN position. With scan tool, observe Passlock(tm) code in BCM data list. If Passlock(tm) code indicates OPEN, see DTC B2958: PASSLOCK(tm) SENSOR DATA CIRCUIT HIGH under DIAGNOSTIC TESTS. If Passlock(tm) code does not indicate OPEN, see SYMPTOM INDEX table under SYMPTOM TESTS.
If scan tool displays any DTCs beginning with "U", diagnose and repair DTCs as necessary. See appropriate BODY CONTROL MODULES article. If scan tool does not display any DTCs beginning with "U", go to next step.
If scan tool displays DTC B2947, B2948, B2957, B2958, B2960, B3031 or B3033, see DIAGNOSTIC TROUBLE CODE INDEX table. If none of these DTCs are displayed, see appropriate BODY CONTROL MODULES article.

DIAGNOSTIC TROUBLE CODE INDEX

DTC ⁽¹⁾

Description

B2947

Passlock(tm) Sensor Power Circuit Low

B2948

Passlock(tm) Sensor Power Circuit High

B2957

Passlock(tm) Sensor Data Circuit Low

B2958

Passlock(tm) Sensor Data Circuit High

B2960