Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSCHEVROLET2001CHEVY EXPRESS G2500, VAN CARGO EXTENDED, 5.7 R, L31/KL8REPAIR AND DIAGNOSISBODY & FRAMEDOOR LOCKSTHEFT DETERRENT SYSTEMSELF-DIAGNOSTIC SYSTEMTHEFT DETERRENT DIAGNOSTIC SYSTEM CHECK
2001 Chevrolet Chevy Express G2500, Van Cargo Extended, 5.7 R, L31/KL8
Theft Deterrent Diagnostic System Check
2001 Chevrolet Chevy Express G2500, Van Cargo Extended, 5.7 R, L31/KL8SECTION Theft Deterrent Diagnostic System Check
- Turn ignition switch to OFF position. Connect scan tool to Data Link Connector (DLC), located below steering column. See Figure . Turn ignition switch to RUN position. If scan tool powers up, go to next step. If scan tool does not power up, go to TEST A: SCAN TOOL DOES NOT POWER UP under SYSTEM TESTS in BODY CONTROL MODULES - CHEVY EXPRESS & SAVANA article.
- Using scan tool, attempt to communicate with Powertrain Control Module (PCM) and Passlock(tm) module. If scan tool communicates with PCM and Passlock(tm) module, go to next step. If scan tool does not communicate with PCM or Passlock(tm) module, see TEST B: SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE under SYSTEM TESTS in BODY CONTROL MODULES - CHEVY EXPRESS & SAVANA article.
- Select DISPLAY DTCs function on scan tool for PCM and Passlock(tm) module. If scan tool displays any DTCs go to step Β 5 . If can tool does not display any DTCs, go to next step.
- Momentarily rotate ignition switch to CRANK position, but do not start engine. Release ignition switch to RUN position. Using scan tool, observe PASSLOCK CODE in Passlock(tm) module SECURITY DATA LIST. If scan tool displays OPEN, go to DTC B2958: PASSLOCK(tm) SENSOR DATA CIRCUIT HIGHΒ . If scan tool does not display OPEN, repair by symptom. Go to SYMPTOM INDEXΒ table under SYSTEM TESTS.
- If scan tool displays DTCs which begin with "U", see TEST B: SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE under SYSTEM TESTS in BODY CONTROL MODULES - CHEVY EXPRESS & SAVANA article. If other DTCs are displayed, go to next step.
- If scan tool does not display DTCs P0601, P0602, P0603, P0604, P0605, P0606, P1612 or P1627, go to next step. If scan tool displays DTCs P0601, P0602, P0603, P0604, P0605, P0606, P1612 or P1627, see appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.
- If scan tool displays DTCs B1007, go to DTC B1007: CHECKSUM VALUE ERROR under DIAGNOSTIC TESTS in BODY CONTROL MODULES - CHEVY EXPRESS & SAVANA article. If scan tool does not display B1007, go to next step. If scan tool displays any other DTCs, perform appropriate test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS table in BODY CONTROL MODULES - CHEVY EXPRESS & SAVANA article.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- β’ You smell fuel, burning insulation, or see smoke.
- β’ Brakes feel soft, pull hard to one side, or make grinding noises.
- β’ The engine overheats, stalls repeatedly, or misfires under load.
- β’ You are missing required tools, torque specs, or safe lifting equipment.
- β’ You are not confident in the next step or safety outcome.