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Home >> Hummer >> 2008 >> H2 4D Utility Wagon >> Repair and Diagnosis >> External Pages >> Different car >> Section 369 (Engine Controls And Fuel - 5.3L, 6.0L & 6.2L - DTC P0010 Through DTC P0442) >> Diagnostic Information and Procedures >> DTC P025A >> Circuit/System Description

Circuit/System Description

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The engine control module (ECM) supplies voltage to the fuel pump control module when the ECM detects that the ignition is on. The voltage from the ECM to the fuel pump control module remains active for 2 seconds, unless the engine is in crank or run. While this voltage is being received, the fuel pump control module supplies a varying voltage to the fuel tank pump module in order to maintain the desired fuel rail pressure.