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Home >> GMC >> 2006 >> Envoy 4.2 S, 4WD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - 4.2L - DTC P2101 To P2444 >> DTC P2431 >> Circuit/System Testing

Circuit/System Testing

  1. With the ignition ON and the engine OFF, observe the AIR Pressure Sensor parameter with a scan tool while manipulating all related wiring and connectors.
    • If manipulation does affect the AIR Pressure Sensor parameter, repair the harness or connector.
  2. With the ignition ON, the engine OFF, and the solenoid valve disconnected, measure for 5 volts between the 5-volt reference circuit and ground.
    • If more than 5 volts, test the 5-volt reference circuit for a short to voltage or a faulty control module.
    • If less than 5 volts, test the 5-volt reference circuit for high resistance, a short to ground, or a faulty control module.
  3. With the ignition ON, the engine OFF, and the solenoid valve disconnected, measure for 0 volts between the low reference circuit and ground.
    • If more than 0 volts, test the low reference circuit for a short to voltage or a faulty control module.
  4. With the ignition ON, the engine OFF, the solenoid valve disconnected, inspect for an AIR Pressure Sensor parameter reading on a scan tool of 0 volts.
    • If more than 0 volts, test the signal circuit for a short to voltage or a faulty control module.
  5. With the ignition ON, the engine OFF, the solenoid valve disconnected, and a 3-amp fused jumper wire connected between the signal and a 5-volt reference circuits, inspect for an AIR Pressure Sensor parameter reading on a scan tool of 5 volts.
    • If less than 5 volts, test the signal circuit for high resistance, a short to ground, or a faulty control module.
  6. With the ignition ON, the engine OFF, the solenoid valve disconnected, a 300 ohm fixed resistor, an appropriate length of secondary ignition wire may be adequate, installed between the 5-volt reference circuit and the low reference circuit, and a 3-amp fused jumper connected from the signal circuit to the 5-volt reference circuit at the fixed resistor, observe an AIR pressure sensor parameter reading on a scan tool of 5 volts.
    • If less than 5 volts, test the 5-volt reference circuit and the signal circuit for high resistance or a faulty control module.
  7. With the ignition ON, the engine OFF, the solenoid valve disconnected, a 300 ohm fixed resistor, an appropriate length of secondary ignition wire may be adequate, installed between the 5-volt reference circuit and the low reference circuit, and a 3-amp fused jumper connected from the signal circuit to the low reference circuit at the fixed resistor, inspect for a pressure sensor parameter reading on a scan tool of 0 volts.
    • If more than 0 volts, test the low reference circuit for high resistance or a faulty control module.
  8. If all circuits and the control module test OK, replace the solenoid valve.
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