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Home >> Chevrolet >> 2001 >> Camaro Base, 2D Convertible, Automatic >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> Engine Control System Self-Diagnostics - 3.8L >> Diagnostic Tests >> DTC P0150: Ho2S Circuit Malfunction - Bank 2, Sensor 1 >> Diagnostic Procedures

Diagnostic Procedures

  1. If powertrain diagnostic system check was performed, go to next step. If powertrain diagnostic system check was not performed, go to POWERTRAIN DIAGNOSTIC SYSTEM CHECK  under DIAGNOSTIC SYSTEM CHECKS. After performing powertrain diagnostic system check, go to next step.
  2. Clear DTCs using scan tool. Reset fuel trim values. Start and idle engine until normal operating temperature is reached. Using scan tool, observe HO2S voltage for suspect sensor. If HO2S voltage is fixed within 300-600 mV, go to step  4. If HO2S voltage is not fixed within 300-600 mV, go to next step.
  3. Condition that set this DTC is not present. DTC may have been set by HO2S connector water intrusion, intermittent open in HO2S high signal circuit, intermittent open in HO2S low signal circuit, HO2S low signal circuit with high resistance to ground, PCM ground circuits with high resistance to ground, inoperative HO2S heater, poor HO2S or PCM connector terminal connection, exhaust system leak or defective HO2S. Repair problem as necessary. After repairs, go to step  17. If problem was not found, go to INTERMITTENT TROUBLE CODE DETERMINATION  under SELF-DIAGNOSTIC SYSTEM.
  4. Turn ignition off. Disconnect suspect HO2S connector. Jumper HO2S connector terminal "A" (Tan/White wire on Bank 1, Sensor 1; Tan wire on Bank 2, Sensor 1; Gray wire on Bank 1, Sensor 2) to a known good ground. Jumper HO2S connector terminal "B" (Purple/White wire on Bank 1, Sensor 1; Purple wire on Bank 2, Sensor 1; Dark Blue wire on Bank 1, Sensor 2) to a known good ground. Turn ignition on. Using a scan tool, observe HO2S voltage for suspect sensor. If voltage measures less than 20 mV, go to step  7. If voltage is 20 mV or more, go to next step.
  5. Turn ignition off. Remove jumper wires from HO2S terminals. Disconnect PCM connectors C1 and C2. Using a DVOM, measure continuity of wiring between PCM and HO2S connector terminals "A" (Tan/White wire on Bank 1, Sensor 1; Tan wire on Bank 2, Sensor 1; Gray wire on Bank 1, Sensor 2) and "B" (Purple/White wire on Bank 1, Sensor 1; Purple wire on Bank 2, Sensor 1; Dark Blue wire on Bank 1, Sensor 2). If resistance in both circuits is less than 5 ohms, go to next step. If resistance in either circuit is 5 ohms or more, go to step  9.
  6. Check for poor connections at PCM connector. Repair wiring as necessary. After repairs, go to step  17. If connections are okay, go to step  16.
  7. Remove jumper wires from HO2S terminals. Connect test light between HO2S connector terminals "C" (Black wire) and "D" (Pink wire). Turn ignition on. If test light illuminates, go to next step. If test light does not illuminate, go to step  10.
  8. Turn ignition off. Reconnect HO2S connector. Disconnect PCM connector C1. Using DVOM, measure resistance between appropriate PCM connector C1 terminal (No. 12 on Bank 1, Sensor 1; No. 29 on Bank 2, Sensor 1; No. 28 on Bank 1, Sensor 2) and one of the PCM ground circuit terminals. If resistance is less than 500 ohms, go to step  12. If resistance is 500 ohms or more, go to step  11.
  9. Repair wiring that measured high resistance. After repairs, go to step  17.
  10. Repair wiring to HO2S connector terminals "C" (Black wire) and "D" (Pink wire) for open or high resistance, poor ground connection, or open ENG SEN fuse (20-amp). After repairs, go to step  17.
  11. Repair high resistance in wiring between HO2S connector terminal "A" (Tan/White wire on Bank 1, Sensor 1; Tan wire on Bank 2, Sensor 1; Gray wire on Bank 1, Sensor 2) and PCM ground circuit. Probable causes include the following:
    • Poor HO2S connector terminal connection.
    • Open sensor harness low signal circuit, this requires HO2S replacement.
    • Sensor harness low signal circuit with high resistance, this requires HO2S replacement
    • Poor PCM ground connection.
    • High PCM ground circuit resistance.
    • Ungrounded exhaust system.

    After repairs, go to step  17.

  12. Inspect for exhaust system leaks upstream of suspect HO2S. Leak may be very small and will typically be within 12" of suspect HO2S. Repair exhaust as necessary. After repairs, go to step  17. If no problem was found, go to next step.
  13. Allow engine to cool to ambient temperature. Using a DVOM, measure resistance between HO2S connector terminal "A" (Tan/White wire on Bank 1, Sensor 1; Tan wire on Bank 2, Sensor 1; Gray wire on Bank 1, Sensor 2) and a PCM ground circuit terminal. If resistance is less than 500 ohms, go to step  15. Of resistance is 500 ohms or more, go to next step.
  14. Remove suspect HO2S from exhaust. Clean HO2S mounting threads. Apply anti-seize sensor threads. Tighten HO2S to specification. Using a DVOM, measure resistance between HO2S connector terminal "A" (Tan/White wire on Bank 1, Sensor 1; Tan wire on Bank 2, Sensor 1; Gray wire on Bank 1, Sensor 2) and a PCM ground circuit terminal. If resistance is less than 500 ohms, go to step  17. Of resistance is 500 ohms or more, go to next step.
  15. Replace HO2S. After repairs, go to step  17.
  16. Replace PCM. After repairs, go to next step.
  17. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine and allow it to reach normal operating temperature. Operate vehicle within 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 function. If any undiagnosed DTCs are displayed, go to applicable DTC test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no undiagnosed DTCs are displayed, system is okay.
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