LEMON Manuals: Even more car manuals for everyone
Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1863 (Engine Controls And Fuel - 2.4L (Lat) - DTC P0420 To DTC P2544) >> DTC P0641 or P0651 >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2007 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
IMPORTANT: Additional DTCs will set when disconnecting the components.
  1. Ignition OFF, disconnect the harness connector of all appropriate sensors for the applicable DTC.
    2. IMPORTANT: A short to voltage on the signal circuit of certain components may cause this DTC to set.
  2. Ignition ON, measure for 4.8-5.2 volts between one of the 5-volt reference circuits and ground.
    • If the voltage is less than the specified value, test for a short to ground on all the 5-volt reference circuits. If all circuits test normal, replace the control module.
    • If the voltage is greater than the specified value, test for a short to voltage on all the 5-volt reference circuits, or the signal circuit, for each component associated with the appropriate 5-volt reference circuit. If all circuits test normal, replace the control module.
  3. Connect each component associated with the 5-volt reference circuit, one at a time, while monitoring the voltage. The voltage should not change more than 1 volt.
    • If the voltage display changes more than the specified value when a component is connected, replace the component.
scientia non olet · About LEMON Manuals