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Home >> Chevrolet >> 2001 >> Venture Base, Van Passenger >> Repair and Diagnosis >> External Pages >> Different car >> Section 73 (Engine Controls Self-Diagnostics - 5.7L Corvette) >> Diagnostic Tests >> DTC P0140 & P0160: Ho2S Circuit - Insufficient Activity - Bank 1 & 2, Sensor 2 >> Diagnostic Procedures

Diagnostic Procedures

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  1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM.
    2. NOTE: Inspect the HO2S for being secure before proceeding with this DTC. A loose sensor could cause this DTC to set.
  2. Install a scan tool. Start the engine and idle the engine at the normal operating temperature. Change the throttle position more than 5 percent within 1 second, 6 times. Observe the HO2S voltage with a scan tool. Is the HO2S voltage outside 410-490 mV? If yes, go to next step. If no, go to step  4.
  3. Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or as close to the Freeze Frame/Failure Records data that you observed. Does the DTC fail this ignition cycle? If yes, go to next step. If no, see INTERMITTENT CONDITIONS  under SELF-DIAGNOSTIC SYSTEM.
  4. Turn ON the ignition, with the engine OFF. Disconnect the HO2S. Jumper the HO2S high signal circuit to a known-good ground. Jumper the HO2S low signal circuit to a known-good ground. Observe the HO2S voltage with a scan tool. Is the HO2S voltage below 200 mV? If yes, go to step  8. If no, go to next step.
  5. Remove both jumper wires. Use the DMM in order to measure the voltage from the HO2S low signal circuit to a battery ground. Is the voltage near 5V? If yes, go to next step. If no, go to step  7.
  6. Turn OFF the ignition. Disconnect the PCM connector C1. Test for continuity of the HO2S high signal circuit. If no continuity is indicated on the DMM, repair the open circuit. Did you find and correct the condition? If yes, go to step  12. If no, go to step  10.
  7. Turn OFF the ignition. Disconnect the PCM connector C1. Test for continuity of the HO2S low signal circuit. If no continuity is indicated on the DMM, repair the open or the faulty connection. Did you find and correct the condition? If yes, go to step  12. If no, go to step  10.
  8. Inspect the HO2S circuits for a faulty connection at the HO2S harness connector. If you find a faulty connection, replace or repair the terminal as necessary. Did you find and correct the condition? If yes, go to step  12. If no, go to next step.
  9. Replace the affected HO2S. Did you complete the replacement? After repairs, go to step  12.
  10. Inspect the HO2S circuits for a faulty connection at the PCM. If you find a faulty connection, replace or repair the terminal as necessary. Did you find and correct the condition? If yes, go to step  12. If no, go to next step.
  11. Replace the PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram PCM. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After repairs, go to next step.
  12. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step  2.
  13. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.
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