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Fuel Pump Control Circuit

CAUTION: To prevent fuel pump damage, DO NOT  operate fuel pump for more than 10 seconds.
  1. Check fuel pump operation. See FUEL PUMP OPERATION (USING DLC NO . 1). If fuel pump operates, go to step 3). If fuel pump does not operate, check ECM keyed (ignition) power circuit. See ECM KEYED (IGNITION) POWER CIRCUIT under COMPUTERIZED ENGINE CONTROLS .
  2. If circuit is okay, check fuel pump operation. See FUEL PUMP OPERATION (USING FUEL PUMP CONNECTOR) . If fuel pump operates, measure fuel pump resistance. See FUEL PUMP RESISTANCE . If fuel pump resistance is as specified, repair open circuit between fuel pump and terminal FP of DLC No. 1, or between fuel pump and chassis ground.
  3. Check circuit opening relay. See RELAYS under MODULES , MOTORS, RELAYS & SOLENOIDS. If circuit opening relay is okay, remove glove compartment. Measure voltage between chassis ground and terminal No. 18 (Green/Red wire) of ECM connector E8. See COMPONENT LOCATIONS  under INTRODUCTION. To identify ECM connectors and terminals, see Figure.
  4. If battery voltage is present, replace ECM. If battery voltage is not present, check for open circuit between EFI main relay and circuit opening relay, and between circuit opening relay and ECM.
  5. If circuits are okay, remove circuit opening relay. While cranking engine, measure voltage between chassis ground and terminal No. 3 (Black/White wire) of socket where circuit opening relay was installed (corresponding terminal on relay is ST). See Figure-15.
  6. If battery voltage is present, repair open circuit between chassis ground and terminal No. 6 (White/Black wire) of socket where circuit opening relay was installed (corresponding terminal on relay is E1). If battery voltage is not present, remove glove box.
  7. While cranking engine, measure voltage at terminal No. 13 (Black/White wire) of ECM connector E7. If 6 volts or more is present, repair open White/Black wire between chassis ground and terminal No. 6 of circuit opening relay. If ECM is receiving a starter signal, replace ECM.
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