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 MANUALSCHEVROLET1998SUBURBAN K2500, 7.4 J, PART TIMEREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 44 (ANTI-THEFT SYSTEM)DIAGNOSTIC TESTSDTC B0688: SECURITY INDICATOR LIGHT CIRCUIT HIGHTESTING
1998 Chevrolet Suburban K2500, 7.4 J, Part Time
DTC B0688: Security Indicator Light Circuit High: Testing
1998 Chevrolet Suburban K2500, 7.4 J, Part TimeSECTION Testing
WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 1998 GMC Savana Special, 1998 GMC Savana Camper Special, 1998 GMC Savana, 1998 Chevrolet RV Cutaway, and 1998 Chevrolet Cutaway. However, it is still accessible from the selected car via links, so may be relevant.
- Perform system check. See SYSTEM CHECK under SYSTEM TESTS. Go to next step.
- Turn ignition on. If gauges and lights are inoperative, see INSTRUMENT PANEL article. If gauges and lights are okay, go to next step.
- Using scan tool, turn SECURITY indicator light on. If light illuminates, turn ignition off. Replace PASSLOCK(R) module. See PASSLOCK(R) MODULE under REMOVAL & INSTALLATION. Go to step 8). If light does not illuminate, go to next step.
- Turn ignition off. Remove instrument cluster. See INSTRUMENT PANEL article. Connect test light between instrument cluster harness connector terminal A4 (Yellow wire) and battery voltage. Turn ignition on. Using scan tool, turn SECURITY indicator light on. If test light illuminates, go to next step. If test light does not illuminate, go to step 6).
- Remove and inspect bulb. If bulb is faulty, replace bulb. If bulb is okay, check instrument cluster printed circuit for open circuit. Repair or replace as necessary. Go to step 8).
- Turn ignition off. Disconnect scan tool and test light. Disconnect PASSLOCK(R) module connector. Check voltage at PASSLOCK(R) module harness connector terminal B2 (Yellow wire). If voltage is less than one volt, go to next step. If voltage is one volt or more, repair short to voltage in Yellow wire between PASSLOCK(R) module harness connector terminal B2 and instrument cluster harness connector terminal A4. Go to step 8).
- Check resistance of Yellow wire between PASSLOCK(R) module harness connector terminal B2 and instrument cluster harness connector terminal A4. If resistance is less than 10 ohms, replace PASSLOCK(R) module. See PASSLOCK(R) MODULE under REMOVAL & INSTALLATION. Go to next step. If resistance is 10 ohms or more, repair Yellow wire. Go to next step.
- Reconnect all connectors and components. Turn ignition on. Using scan tool, clear all DTCs. Perform reprogramming procedure. See PROGRAMMING. Perform SYSTEM CHECK under SYSTEM TESTS.
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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.