Diagnostic Aids

1994 Ford Aerostar Van Cargo Extended, 3.0 U, StandardSECTION Diagnostic Aids

When ignition switch is in the ON or START position, the PCM connects FUEL PUMP circuit (PCM terminal No. 22) to ground. The fuel pump relay is energized and electrical current flows to the fuel pump. If PCM does not receive ignition PIP signal within 2 seconds, FUEL PUMP circuit is opened and fuel pump operation is terminated. Perform this test when instructed by QUICK TEST or CIRCUIT TEST AA.

This test is only intended to diagnose:

  • Fuel pump relay.
  • Inertia Fuel Shutoff (IFS) switch.
  • Wiring harness circuits (B+, VPWR, FUEL PUMP, GND and POWER-TO-PUMP).
  • Faulty Powertrain Control Module (PCM).
Fig 1: Fuel Pump Monitor Schematic Diagram (J1 - Typical) Fuel Pump Circuit (Relay & Inertia Switch)
G93E76319
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.