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HOMESERVICE MANUALSPONTIAC2006WAVE BASE, 4D SEDAN, Y4M/MLMREPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCETESTING & DIAGNOSISENGINE CONTROLS - 1.6L (L91) - DTC P0420 TO DTC P2076DTC P2076, P2077, OR P2078CIRCUIT/SYSTEM TESTING
2006 Pontiac Wave Base, 4D Sedan, Y4M/MLM

Circuit/System Testing

2006 Pontiac Wave Base, 4D Sedan, Y4M/MLMSECTION Circuit/System Testing
  1. Ignition OFF, disconnect the harness connector of the IMT valve position sensor.
  2. Ignition OFF, test for less than 5 ohms of resistance between the low reference circuit terminal 3 and ground.
      IMPORTANT: If the circuit is shorted to a voltage, the low reference circuit within the ECM may open and the ECM will also need to be replaced.
    • If greater than 5 ohms, test the low reference circuit for a short to voltage, or an open/high resistance. If the circuit/connections test normal, replace the ECM.
    3. IMPORTANT: The 5-volt reference circuits are internally and externally connected at the ECM. Other component DTCs may be set. If other DTCs are set, review the electrical schematic and diagnose the applicable circuits and components.
  3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal 1 and ground.
    • If less than 4.8 volts, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit/connections test normal, replace the ECM.
    • If greater than 5.2 volts, test the 5-volt reference circuit for a short to voltage. If the circuit/connections test normal, replace the ECM.
  4. Verify the scan tool IMT valve position sensor percentage parameter is less than 5 percent.
    • If greater than 5 percent, test the signal circuit for a short to voltage. If the circuit/connections test normal, replace the ECM.
  5. Install a 3-amp fused jumper wire between the signal circuit terminal 2 and the 5-volt reference circuit terminal 1. Verify the scan tool IMT valve position sensor voltage parameter is greater than 95 percent.
    • If less than 95 percent, test the signal circuit for a short to ground or an open/high resistance. If the circuit/connections test normal, replace the ECM.
  6. If all circuits/connections test normal, replace the IMT valve position sensor.
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Stop DIY work and contact a certified mechanic immediately if any of the following apply:

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  • • You are missing required tools, torque specs, or safe lifting equipment.
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