E019

ECM Code E019:

DFI Fuel Pump Circuit:

DESCRIPTION:

The fuel pump receives power from CKT 120. CKT 120 is fed by two alternative sources; the fuel pump relay, and the oil pressure switch. The relay is controlled by the ECM. The relay is energized by the ECM for 2 seconds at key "ON" to provide fuel pressure for starting. After the 2 second fuel pump run, the ECM will not power the relay again until distributor reference pulses are received indicating that the engine is turning (crank or run).

The oil pressure switch is provided as a "backup". Normal operating engine oil pressure will close the normally open oil pressure switch contacts, providing a connection between CKT 239 and 120. If a relay fault occurs, the engine will continue to run as the oil pressure switch powers the fuel pump. A vehicle with the relay inoperative will crank until oil pressure builds (oil telltale light off) then start and run as the oil pressure switch provides power to the fuel pump. The ECM monitors voltage on the fuel pump power CKT 120 to detect fuel pump voltage supply faults. Code E019 is set when (the fuel pump feedback (ECM pin D9) is at 11.0 volts or greater when the fuel pump feed voltage should be 0 volts.

TEST CONDITIONS:

1. Code EO18 clear.
2. RPM = 0.
3. Crank input to ECM at 0 volts (not cranking).
4. "Coolant" light in bulb check (key "on" engine off).

FAILURE CONDITIONS:

Fuel pump feedback voltage greater than or equal to 11.0 volts for 7 seconds. (Fuel pump powered with engine not running.)

ACTION TAKEN:

1. ECM turns on "SERVICE ENGINE SOON" telltale.
2. ECM commands BCM to display "SERVICE SOON" message on CCDIC.

NOTES ON FAULT TREE.

1. At key on engine off, the fuel pump should not be running and the fuel pump feedback (ECM parameter ED10) should show 0 volts. Note: The fuel pump runs for 2 seconds, then turns off at the start of each key "ON" cycle. After the initial 2 second run, the fuel pump will not be powered until the ECM sees distributor reference pulses from the HEI.

2. This branch of the tree checks for oil pressure switch contacts shorted, powering the fuel pump at all times.

3. Checking for fuel pump relay providing fuel pump power due to a relay or relay drive circuit fault.

4. Checking CKT 120 for a short to a 12 volt source.

5. Checking ECM relay drive circuit for a fault that allows fuel pump relay coil to be energized continuously at key on.

NOTE ON INTERMITTENTS:

Probe the fuel pump test point with a voltmeter to ground. Key on and observe voltmeter - it Should read battery voltage for 2 seconds then drop to 0. If the voltmeter stays at battery voltage for longer than 2 seconds, check for fuel pump relay contacts sticking. Repeat the test several times. Continue probing the fuel pump test point to ground and crank and start engine then key off - voltage should drop immediately to 0. If not, check oil pressure switch for sticking contacts.

Review the snapshot data parameters stored with this code to verify failure condition. If the failure condltion is verified, check and repair intermittent wiring connection, or sensor.