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 MANUALSCHEVROLET1999CHEVY EXPRESS G1500, VAN CARGO, 5.7 RREPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCESYSTEMENGINE CONTROL SYSTEM - TESTS W/CODES - DTC P1537-U1193DTC P1626DTC P1626: THEFT DETERRENT SYSTEM FUEL ENABLE CIRCUIT (3.1L "W" BODY)DIAGNOSTIC PROCEDURES
1999 Chevrolet Chevy Express G1500, Van Cargo, 5.7 R
Diagnostic Procedures
1999 Chevrolet Chevy Express G1500, Van Cargo, 5.7 RSECTION Diagnostic Procedures
- Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
- Attempt to select vehicle theft deterrent system data with scan tool. If data can be displayed, go to next step. If data cannot be displayed, go to step 5.
- Turn ignition off. Disconnect PCM and BCM harness connectors. Check serial data circuit for an open between BCM and PCM. Repair as necessary. After repairs, go to step 6. If circuit is okay, go to next step.
- Check serial data circuit for poor connections at PCM. Repair as necessary. After repairs, go to step 6. If problem is found, see DIAGNOSTIC AIDS .
- Check serial data circuit for poor connections at BCM. Repair as necessary. After repairs, go to next step. If circuit is okay, diagnose theft deterrent system.
- Using scan tool, review and record scan tool FAILURE RECORDS data. Clear DTC. Attempt to start engine. If engine starts and continues to run, system is okay. If engine does not start or starts and then stalls, repeat step 2.
NOTE:
If a loss of DLC data has already been diagnosed using the DLC diagnostic, clear this DTC and continue diagnosis with Powertrain OBD System Check.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.