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Test NS-5A: Checking Fuel Pump

NOTE: For connector terminal identification, see CONNECTOR IDENTIFICATION  . For circuit identification and wiring diagram, see WRANGLER wiring diagram in WIRING DIAGRAMS article.
  1. Turn ignition off. Disconnect fuel pump connector. Fuel pump is located in fuel pump module. Fuel pump module is located in fuel tank. Clean and/or repair connector as necessary. Using an ohmmeter, check resistance between ground and fuel pump connector, ground circuit. If resistance is less than 5 ohms, reconnect fuel pump connector and go to next step. If resistance is 5 ohms or more, repair open ground circuit. Perform TEST VER-1A.
  2. Ensure ignition is off. Remove fuel pump relay. Fuel pump relay is located in Power Distribution Center (PDC). PDC is located next to battery. Refer to label under PDC cover for relay location. Clean and/or repair connector as necessary. Substitute a known-good fuel pump relay and attempt to start engine. If engine starts, replace original fuel pump relay. Perform TEST VER-1A. If engine does not start, go to next step.
  3. Ensure ignition is off. Ensure fuel pump relay is still removed. Turn ignition on, with engine off. Using a voltmeter, check voltage on fuel pump relay connector, fused B+ circuit. If voltage is 10 volts or less, repair open fused B+ circuit. Perform TEST VER-1A. If voltage is more than 10 volts, reinstall original relay and go to next step.
  4. Turn ignition off. Disconnect fuel pump connector. Clean and/or repair connector as necessary. Turn ignition on, with engine off. Using scan tool, actuate fuel system. Use an external voltmeter to check voltage on fuel pump relay output circuit between fuel pump relay and PCM. PCM is located in engine compartment. See PCM LOCATION table under SYSTEM DIAGNOSTICS. If voltage is 10 volts or less, repair open fuel pump relay output circuit. Perform TEST VER-1A. If voltage is more than 10 volts, go to step 8).
  5. Ensure ignition is on, with engine off. Using a 12-volt test light connected to ground, probe fuel pump connector, fuel pump relay output circuit. If test light does not illuminate brightly, repair open fuel pump relay output circuit. Perform TEST VER-1A. Of test light illuminates brightly, go to next step.
  6. Turn ignition off. Ensure fuel pump connector is still disconnected. Using scan tool, stop fuel system actuation. Using an ohmmeter, check resistance between ground and fuel pump connector, fuel pump ground circuit. If resistance is 5 ohms or more, repair open fuel pump ground circuit. Perform TEST VER-1A. If resistance is less than 5 ohms, go to next step.
    WARNING: Fuel system may be under pressure. Release fuel pressure before opening system for testing or component replacement. See FUEL PRESSURE RELEASE  .
  7. Ensure ignition is off. Ensure fuel pump connector is still disconnected. Visually inspect fuel pump connector and wiring harness for damage. Repair fuel pump connector and wiring harness as necessary. Perform TEST VER-1A. If fuel pump connector and wiring harness are okay, go to next step.
  8. At this time, fuel pump is assumed to be defective. Replace fuel pump module. Perform TEST VER-1A.
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