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HOMESERVICE MANUALSCHEVROLET2000CHEVY EXPRESS G3500, VAN PASSENGER, 7.4 JREPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCESYSTEMENGINE CONTROL SYSTEM SELF-DIAGNOSTICS - GASOLINE - 4.3L, 5.0L, 5.7L & 7.4LDIAGNOSTIC TESTSDTC P0154: HO2S CIRCUIT - INSUFFICIENT ACTIVITY - BANK 2, SENSOR 1DIAGNOSTIC PROCEDURES
2000 Chevrolet Chevy Express G3500, Van Passenger, 7.4 J

Diagnostic Procedures

2000 Chevrolet Chevy Express G3500, Van Passenger, 7.4 JSECTION Diagnostic Procedures
  1. Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
  2. Using scan tool, record DTC information from VCM. Clear DTCs and reset fuel trim values. Start and warm engine to normal operating temperature. Monitor HO2S 1 voltage with scan tool. If voltage is fixed at 350-550 mV, go to step  4. If voltage is not fixed at 350-550 mV, go to next step.
  3. Condition required to set DTC is not present at this time. Check for defective HO2S 1, exhaust leaks or intermittent HO2S 1 circuit faults. Repair as necessary. After repairs, go to step  17. If no problems are found, see DIAGNOSTIC AIDS .
  4. Turn ignition off. Disconnect HO2S 1 harness connector. Using jumper wires, jumper HO2S 1 high signal and low circuits to ground. Turn ignition on, with engine off. Monitor HO2S 1 voltage with scan tool. If voltage is less than 20 mV, go to step  7. If voltage is not less than 20 mV, go to next step.
  5. Turn ignition off. Remove jumper wires. Disconnect VCM harness connector containing HO2S 1 high signal and low circuits. Measure resistance of HO2S 1 high signal and low circuits between VCM and HO2S 1 harness connectors. If resistance of both circuits is less than 5 ohms, go to next step. If resistance of either circuit is 5 ohms or greater, go to step  9.
  6. Check for faulty VCM harness connections. Repair as necessary. After repairs, go to step  17. If connections are okay, go to step  16.
  7. Remove jumper wires. Ensure ignition is on. Connect test light between heater ignition feed and heater ground circuits at HO2S 1 harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step  10.
  8. Turn ignition off. Reconnect HO2S 1 harness connector. Disconnect VCM harness connectors containing HO2S 1 low circuit and VCM ground circuits. Measure resistance between HO2S 1 low circuit and one of the VCM ground circuits at VCM harness connector. If resistance is less than 500 ohms, go to step  12. If resistance is not less than 500 ohms, go to step  11.
  9. Repair circuit that measured high resistance. After repairs, go to step  17.
  10. Repair HO2S 1 heater ignition feed or heater ground circuit. After repairs, go to step  17.
  11. Repair high resistance between HO2S 1 low circuit and VCM ground circuit. After repairs, go to step  17.
  12. Check for exhaust leaks upstream of HO2S 1. Repair as necessary. After repairs, go to step  17. If no leaks are found, go to next step.
  13. Allow engine to cool completely. Measure resistance between HO2S 1 low circuit and one of the VCM ground circuits at VCM harness connector. If resistance is less than 500 ohms, go to step  15. If resistance is not less than 500 ohms, go to next step.
  14. Remove HO2S 1. Clean threads, apply anti-seize compound and reinstall. Measure resistance between HO2S 1 low circuit and one of the VCM ground circuits at VCM harness connector. If resistance is less than 500 ohms, go to step  17. If resistance is not less than 500 ohms, go to next step.
  15. Replace HO2S 1. After repairs, go to step  17.
  16. Replace VCM. Program replacement VCM using required equipment. Perform Passlock® reprogramming and CKP system variation learn procedures. After repairs, go to next step.
  17. Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, and then enter this DTC. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step  2.
  18. Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTCs are displayed, go to applicable DTC test. If no undiagnosed DTCs are displayed, system is okay.
RENDER: 1.0x

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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.