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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1996 (Engine Controls And Fuel - 3.5L - DTC P025A/P0300 To DTC P0700) >> DTC P0340 >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2009 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the multi-way engine harness to fuel injector harness connector X111.
  2. Test for less than 1 ohm between ECM side of the low reference circuit terminal P and ground.
    • If greater than the specified value, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
  3. Ignition ON, test for 4.8-5.2 volts between the ECM side of the 5-volt reference circuit terminal N and ground.
    • If less than the specified range, test the 5-volt reference circuit for an open/high resistance or short to ground. If the circuit tests normal, replace the ECM.
    • If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.
  4. Ignition ON, test for 4.8-5.2 volts between the ECM side of the signal circuit terminal R and ground.
    • If less than the specified range, test the signal circuit for an open/high resistance or short to ground. If the circuit tests normal, replace the ECM.
    • If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.
  5. Ignition ON, using a jumper wire connected to ground, momentarily touch the CMP sensor signal circuit terminal R repeatedly. The CMP active counter parameter should increment.
    • If the CMP active counter does not increment, replace the ECM.
  6. Ignition OFF, inspect the wiring harness, from the multi-way connector to the CMP sensor, for any damage, opens, or shorts.
    • If the circuits test normal replace the CMP sensor.
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