Chart A-7A, Fuel System Diagnosis

When ignition is turned on, ECM and control relay will turn on the in-tank fuel pump under the following conditions:

During engine crank
Ignition on, engine running, ECM is receiving ignition signal
Coolant temperature is less than 10°F (-12° C), ignition on for 3 seconds.

It will remain on as long as the engine is cranking or running and the ECM is receiving reference pulses. If there are no reference pulses, ECM will shut off the fuel pump within 3 seconds after key on. Excess fuel is then returned to fuel tank.

NOTE: Test numbers refer to test numbers on diagnostic chart.

This step verifies that fuel pump operates when engine is cranking.
Checks CKT No.s 440, 120, 150 and fuel pump.
Checks control relay.
Checks CKT 465 and ECM ground.