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Home >> Buick >> 2007 >> Allure CX >> Repair and Diagnosis >> External Pages >> Different car >> Section 70 (Engine Control System & Fuel System - 3.8L - DTC P0385 To DTC P2108) >> DTC P0451, P0452, P0453, or P0454 >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2008 Buick LaCrosse and 2008 Buick Allure. However, it is still accessible from the selected car via links, so may be relevant.
  1. With the ignition OFF, disconnect the harness connector at the FTP sensor.
  2. Ignition OFF, test for less than 5 ohms between the low reference circuit terminal A and ground.
    • If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the PCM.
  3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal C and ground.
    • 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 tests normal, replace the PCM.
    • If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the PCM.
  4. Verify the scan tool FTP sensor parameter is less than 0.1 volt.
    • If greater than the specified range, test the signal circuit terminal B for a short to voltage. If the circuit tests normal, replace the PCM.
  5. Install a 3A fused jumper wire between the signal circuit terminal B and the 5-volt reference circuit terminal C. Verify the scan tool FTP sensor parameter is greater than 4.7 volts.
    • If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the PCM.
  6. If all circuits test normal, test or replace the FTP sensor.
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