Fuel Pump: Testing and Inspection

Fuel Pump Circuit Schematic:

Refer to the schematic diagram and test the system with the diagnostic chart.


FUEL PUMP CIRCUIT DIAGNOSTIC CHART

Fuel Pump Circuit Diagnostic Chart:

CHECK FUEL PUMP OPERATION IN "D-CHECK" MODE
1. Connect "Test Mode" connector. [1]
2. Turn ignition "ON."
3. Check fuel pump for proper operation. Fuel pump should cycle on and off.

[1] Refer to "How To Display and Read Diagnostic Trouble Codes" in COMPUTERS AND CONTROL SYSTEMS.


CHECK FUEL PUMP RELAY

Fuel Pump Relay Testing:

1. Disconnect relay connector and remove relay from its bracket.
2. Measure resistance of relay coil between terminals #1 and #3. It should read 70 Ohms.
3. Connect 12V to relay coil terminals and check continuity between switching terminals. Connect battery "+" to terminal #1 and battery "-" to terminal #3. Relay should "click" when energized.

Terminal: Resistance:
2 - 4 0 Ohms


CHECK FUEL PUMP RELAY VOLTAGE
With relay connector attached, measure voltage between relay connector terminal (B30)1 and ground. It should read 10V minimum.


CHECK ECU VOLTAGE
Check ECU voltage with ignition "ON" and also while cranking engine:

Connector
& terminal: Voltage:
(F47)9 - Ground 10V min. (ignition "ON")
.................... 0V (engine cranking)


CHECK FUEL PUMP TERMINAL VOLTAGE

Fuel Pump Terminal Voltage:

1. Remove fuel pump access cover in trunk and disconnect fuel pump.
2. While cranking engine, measure voltage between connector terminal (R22)1 and ground. It should read 10V minimum.


CHECK FUEL PUMP
1. Disconnect fuel pump connector.
2. Connect 12V to the proper terminals and check fuel pump operation:

Terminal: Connection:
#1 Battery "+"
#3 Battery "-"