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Home >> Chevrolet >> 2006 >> Epica LT >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - 2.5L (LBK) - DTC P0030 To DTC P0230 >> DTC P0136 or P0156 >> Circuit/System Testing

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector of the appropriate HO2S sensor.
  2. Ignition ON, verify that the HO2S parameter is between 350-500 mV.
    • If less than 350 mV, test the signal circuit of the HO2S sensor for a short to ground. If the circuit/connections test normal, replace the ECM.
    • If greater than 500 mV, test the signal circuit of the HO2S sensor for a short to voltage. If the circuit/connections test normal, replace the ECM.
    3. IMPORTANT: The test lamp is used to load the circuit and may not illuminate.
  3. Connect a test lamp between the low reference circuit of the HO2S sensor and the positive terminal of the battery.
  4. Ignition ON, load test for less than 0.1 volt between the low reference circuit of the HO2S sensor and ground.
    • If greater than 0.1 volt, test the low reference circuit of the HO2S for a short to voltage or an open/high resistance. If the circuit/connections test normal, replace the ECM.
  5. Install a 3-amp fused jumper wire between the signal circuit and the low reference circuit of the HO2S sensor and verify the HO2S sensor parameter is less than 60 mV.
    • If greater than 60 mV, test the signal circuit of the HO2S sensor for an open/high resistance. If the circuit/connections test normal, replace the ECM.
  6. If all circuits/connections test normal, replace the HO2S sensor.
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