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Home >> Hummer >> 2008 >> H3 Alpha >> Repair and Diagnosis >> Accessories & Equipment >> Gauges & Instrument Panels >> Displays And Gages >> Diagnostic Information and Procedures >> Engine Oil Pressure Indicator Malfunction (3.7L engine) >> Circuit/System Testing

Circuit/System Testing

IMPORTANT: Do not turn the key to the crank position or engage the starter at any time during diagnosis.
  1. Ignition OFF, disconnect the harness connector at the engine oil pressure (EOP) switch.
  2. Ignition OFF, test for less than 1 ohm between the ground circuit terminal B and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
  3. Ignition ON, verify the scan tool Engine Oil Pressure Switch parameter is OK.
    • If not the specified value, test the signal circuit for a short to ground. If the circuit tests normal, replace the ECM.
  4. Ignition ON, install a 3A fused jumper wire between the signal circuit terminal A and the ground circuit terminal B. Verify the scan tool Engine Oil Pressure Switch parameter is Low.
    • If not the specified value, test the signal circuit for an open/high resistance. If circuit test normal, replace the ECM.
  5. If all circuits test normal, test or replace the engine oil pressure switch.
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