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Home >> Isuzu >> 2007 >> Ascender 4WD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System & Fuel System - 4.2L - DTC P0442 To DTC P2101 >> DTC P0451 >> Circuit/System Testing
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Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the FTP sensor.
  2. Ignition OFF, test for less than 5 ohms of resistance 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 control module.
  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 control module.
    • If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the control module.
  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 control module.
  5. Install a 3-amp 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 short to ground or an open/high resistance. If the circuit tests normal, replace the control module.
  6. If all circuits test normal, test or replace the FTP sensor.
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