Fuel Pump Amperage Test

This amperage (current draw) test is to be done in conjunction with the Fuel Pump Pressure Test, Fuel Pump Capacity Test and Fuel Pressure Leak Down Test. Before performing the amperage test, be sure the temperature of the fuel tank is above 10� C (50� F).




The DRB III(R) Scan Tool along with the DRB III(R) Low Current Shunt (LCS) adapter, and its test leads, will be used to check fuel pump amperage specifications.

1. Be sure fuel tank contains fuel before starting test. If tank is empty or near empty, amperage readings will be incorrect.
2. Obtain LCS adapter (1).
3. Plug cable from LCS adapter (2) into DRB III(R) scan tool at SET 1 receptacle.
4. Plug DRB III(R) into vehicle 16-way connector (data link connector).
5. Connect (-) and (+) test cable leads into LCS adapter receptacles (3). Use 10 amp (10A +) receptacle and common (-) receptacles.
6. Gain access to MAIN MENU on DRB III(R) screen.
7. Press DVOM button on DRB III(R).
8. Using left/right arrow keys, highlight CHANNEL 1 function on DRB III(R) screen.
9. Press ENTER three times.
10. Using up/down arrow keys, highlight RANGE on DRB III(R) screen (screen will default to 2 amp scale).
11. Press ENTER to change 2 amp scale to 10 amp scale. This step must be done to prevent damage to DRBIII(R) Scan Tool or LCS adapter (blown fuse).
12. Remove cover from Control Module Box and remove the fuel pump relay fuse.

WARNING: BEFORE PROCEEDING TO NEXT STEP, NOTE THE FUEL PUMP WILL BE ACTIVATED AND SYSTEM PRESSURE WILL BE PRESENT. THIS WILL OCCUR AFTER CONNECTING TEST LEADS FROM LCS ADAPTER INTO FUEL PUMP FUSE CAVITIES. THE FUEL PUMP WILL OPERATE EVEN WITH IGNITION KEY IN OFF POSITION. BEFORE ATTACHING TEST LEADS, BE SURE ALL FUEL LINES AND FUEL SYSTEM COMPONENTS ARE CONNECTED.

CAUTION: To prevent possible damage to the vehicle electrical system and LCS adapter, the test leads must be connected into fuse cavities.

13. Attach the test leads from LCS adapter into the fuel relay fuse cavities. For location of these cavities.
14. When the LCS adapter test leads are attached to the fuel pump relay fuse cavities, the fuel pump will be activated. Determine fuel pump amperage on DRB III(R) screen. Amperage should be below 9.0 amps. If amperage is below 9.0 amps, and specifications for the Fuel Pump Pressure, Fuel Pump Capacity and Fuel Pressure Leak Down tests were met, the fuel pump is OK.

15. If amperage is more than 9.0 amps, replace the fuel pump assembly. The Electric Fuel Pump is serviced separately.
16. Disconnect test leads from relay fuse cavities immediately after testing.