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Fuel Pump Control Circuit Diagnosis: Metro

  1. Perform diagnostic system check. See POWERTRAIN DIAGNOSTIC SYSTEM CHECK in SELF-DIAGNOSTICS - METRO article. Repair any faults identified and go to next step.
  2. Remove fuel filler cap. With the aid of an assistant, turn ignition on (engine off) and listen for sound of fuel pump operation at fuel filler pipe. Repeat ignition cycle if necessary. If fuel pump does not operate for 2 seconds and then turn off, go to next step. If fuel pump operates for 2 seconds and then turns off, electrical circuit is okay at this time. Condition may be intermittent or fuel system may not be at correct operating pressure. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES - CARS article or FUEL SYSTEM DIAGNOSIS .
  3. If fuel pump does not operate continuously with ignition on (engine off), go to next step. If fuel pump operates continuously with ignition on (engine off), go to step  16.
    4. NOTE: To command fuel pump operation with a scan tool, fuel level must be at least 20 percent and no DTCs should be set.
  4. Turn ignition off. Remove fuel pump relay from relay box. Relay box is located on left side of engine compartment, behind battery. Using a test light connected to battery voltage, probe cavity No. 2 (Pink/White wire) of fuel pump relay socket. See WIRING DIAGRAMS article. Crank engine or use scan tool to activate fuel pump. If test light illuminates, go to next step. If test light does not illuminate, go to step  15.
  5. Using a test light connected to ground, probe cavity No. 4 (White/Blue wire) of fuel pump relay socket. See WIRING DIAGRAMS article. Turn ignition on (engine off). If test light illuminates, go to next step. If test light does not illuminate, go to step  10.
  6. Turn ignition off. Connect a fused jumper wire between cavities No. 3 (Pink wire) and No. 4 (White/Blue wire) of fuel pump relay socket. See WIRING DIAGRAMS article. Turn ignition on (engine off). Check for sound of fuel pump operation at fuel filler pipe. If fuel pump is not operating, go to next step. If fuel pump is operating, go to step  13.
  7. Leave fused jumper wire connected as explained in step  6. Remove rear seat cushion and locate White 2-pin fuel pump connector. Using a test light connected to ground, backprobe terminal No. 1 (Pink wire) of White 2-pin fuel pump connector. See WIRING DIAGRAMS article. If test light illuminates, go to next step. If test light does not illuminate, go to step  11.
  8. Turn ignition off. Disconnect fused jumper wire from fuel pump relay cavities. Disconnect White 2-pin fuel pump connector. Using a test light connected to battery voltage, probe terminal No. 2 (Black wire) on harness side of White 2-pin fuel pump connector. See WIRING DIAGRAMS article. If test light illuminates, go to next step. If test light does not illuminate, go to step  12.
  9. Remove fuel tank. See REMOVAL, OVERHAUL & INSTALLATION article. Check for following conditions:
    • Open circuit between White 2-pin fuel pump connector to fuel sending unit.
    • Faulty connection in electrical connector pass through from fuel sending unit.
    • Remove fuel sending unit and check fuel pump wire harness and electrical connections.
    If no faults are located and repaired, go to step  21. If any fault is located and repaired, go to step  23.
  10. Check for an open in White/Blue wire between main relay and fuel pump relay. See WIRING DIAGRAMS article. Locate and repair circuit as required, and go to step  23. If no repair is required, go to MAIN RELAY CIRCUIT DIAGNOSIS .
  11. Locate and repair open or high resistance in Pink wire between fuel pump relay and White 2-pin fuel pump connector. See WIRING DIAGRAMS article. After repair, go to step  23.
  12. Locate and repair open in Black wire between 2-pin White fuel pump connector and ground point located at rear center of luggage compartment. Also check connection of ground point located at rear center of luggage compartment. See WIRING DIAGRAMS article. After repair, go to step  23.
  13. Turn ignition off. Remove fused jumper wire from fuel pump relay socket cavities. Turn ignition on (engine off). Using a test light connected to ground, backprobe terminal No. 1 (Pink wire) of fuel pump relay socket. See WIRING DIAGRAMS article. If test light does not illuminate, go to next step. If test light illuminates, go to step  20.
  14. Repair open or short in Black/White wire between IG-COIL fuse (15-amp) and fuel pump relay. IG-COIL fuse (15-amp) is located in junction block under left side of instrument panel. Fuel pump relay is located in relay box located on left side of engine compartment, behind battery. Also check condition of IG-COIL fuse (15-amp) and replace as necessary. See WIRING DIAGRAMS article. After repair, go to step  23.
  15. Check for an open in Pink/White wire between PCM connector C1 terminal No. 18 and fuel pump relay terminal No. 2. See WIRING DIAGRAMS article and Fig 1. If open is not present, go to step  22. If open is located and repaired, go to step  23.
  16. Remove fuel pump relay from relay box. Relay box is located on left side of engine compartment, behind battery. If fuel pump continues to operate with relay removed, go to next step. If fuel pump does not continue to operate with relay removed, go to step  18.
  17. Locate and repair short to voltage in Pink wire between fuel pump relay and fuel pump. See WIRING DIAGRAMS article. After repair, go to step  23.
  18. Turn ignition off. Remove fuel pump relay from relay box. Relay box is located on left side of engine compartment, behind battery. Using a test light connected to battery voltage, probe cavity No. 2 (Pink/White wire) of fuel pump relay socket. See WIRING DIAGRAMS article. Turn ignition on and observe test light for 10 seconds. If test light stays illuminated for more than 3 seconds, go to next step. If test light does not stay illuminated for more than 3 seconds, go to step  20.
  19. Check for a short to ground in Pink/White wire between PCM connector C1 terminal No. 18 and fuel pump relay terminal No. 2. See WIRING DIAGRAMS article and Fig 1. If short to ground does not exist, go to step  22. If short to ground is located and repaired, go to step  23.
  20. Replace fuel pump relay. After repair, go to step  23.
  21. Replace fuel pump. After repair, go to step  23.
  22. Replace PCM. After repair, reprogram PCM and go to next step. See PROGRAMMING in SELF-DIAGNOSTICS - METRO article.
  23. Operate vehicle under same conditions as recorded for original symptom. If system operates properly, system is okay at this time. If system does not operate properly, check fuel pump relay and fuel pump. Because temperature may affect fuel pump relay performance, allow vehicle to sit outside overnight and after running engine for 30 minutes. See SYSTEM & COMPONENT TESTING - CARS - METRO & PRIZM article.
Fig 1: Identifying PCM Harness Connectors & Terminals (Metro)
G00057650Courtesy of GENERAL MOTORS CORP.
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