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Home >> Buick >> 1995 >> LeSabre Custom >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> ECM/Pcm Code Charts >> DTC P1626/1629: Pass-Key II Fuel Enable Circuit >> Test Description
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Test Description

NOTE: Test numbers refer to numbers on diagnostic chart.
  1. If vehicle does not crank with Code P1626 or P1629 stored, problem affects entire theft deterrent system and is not isolated to fuel enable circuit.
  2. PCM supplies 5 volts to fuel enable input circuit which theft deterrent module pulses to ground when correct key resistance is recognized. This test ensures PCM is supplying 5 volts and circuit is not open or shorted to ground.
  3. Checks signal from theft deterrent module. DC frequency on circuit should measure approximately 50 hertz.
  4. Checks for a faulty PCM or intermittent condition by clearing Code P1626 or P1629. Since PCM ignores absence of a fuel enable signal only when Code P1626 or P1629 is stored, vehicle should not start if problem is present and Code P1626 or P1629 has been cleared.
Fig 1: Codes P1626/1629 Schematic (3.8L) Pass-Key II Fuel Enable Circuit
G95I13878
Fig 2: Codes P1626/1629 Diagnostic Flow Chart (3.8L) Pass-Key II Fuel Enable Circuit
G94A35303