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 MANUALSCHEVROLET1999SUBURBAN C2500, 6.5 FREPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCESYSTEMENGINE CONTROL SYSTEM - TESTS W/CODES - DTC P0352-P0452DTC P0371DTC P0371: IGNITION CONTROL (IC) MODULE 24X REFERENCE CIRCUIT-TOO MANY PULSES (4.0L "G" BODY & 4.6L "E" & "K" BODIES)DIAGNOSTIC PROCEDURES
1999 Chevrolet Suburban C2500, 6.5 F
Diagnostic Procedures
1999 Chevrolet Suburban C2500, 6.5 FSECTION 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.
- Check for possible cause of Electromagnetic Interference (EMI), such as spark plug wires routed too close to IC module, high power transmitters operating within vicinity or the use of a battery charger. If possible source of EMI is found, remove source. If EMI interference is not noticed, go to next step.
- Clear DTCs and retest. If DTC P0371 resets, go to next step. If DTC P0371 does not reset, fault is not present.
- Check terminal contact of 24X spark reference circuit at IC module and PCM harness connector. Repair as necessary. If terminal contact is okay, go to next step.
- Replace IC module.
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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.