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Home >> Buick >> 2008 >> Allure CXS >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System & Fuel System - 3.6L - DTC P0335 To DTC P2097 >> DTC P0452 or P0453 >> Circuit/System Testing

Circuit/System Testing

  1. Ignition OFF, remove the fuse that supplies B+ to terminal X2-36 of the ECM.
  2. Disconnect the C405 harness connector at the rear of the fuel tank.
  3. Test for less than 5 ohms of resistance between the low reference circuit terminal H and ground, at the ECM side of the connector.
    • If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit/connections test normal, replace the ECM.
  4. Install the fuse that supplies B+ to terminal X2-36 of the ECM.
  5. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal F and ground, at the ECM side of connector C405.
    • If less than the specified range, 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 the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit/connections test normal, replace the ECM.
  6. Verify the scan tool FTP Sensor parameter is less than 4.8 volts
    • If greater than the specified range, test the signal circuit for a short to voltage. If the circuit/connections test normal, replace the ECM.
  7. At the ECM side of C405, install a 3A fused jumper wire between the signal circuit terminal G and the 5-volt reference circuit terminal F. Verify the scan tool FTP Sensor parameter is greater than 4.8 volts.
    • If less than the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit/connections test normal, replace the ECM.
  8. Remove the fuel tank. Refer to Fuel Tank Replacement .
  9. Disconnect the harness connector at the FTP sensor.
  10. Inspect the FTP sensor circuits in the fuel tank harness, between the FTP sensor connector and C405 for the following conditions:
    • Damaged wiring or terminals
    • Open circuits
    • Short to ground
    • Wire to wire short
    • If a condition is located, repair as necessary.
  11. If all circuits/connections test normal, replace the FTP sensor.
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