Fuel Pump Amperage Test
NOTE:
For component locations and connector identification, see COMPONENT LOCATIONS and CONNECTOR IDENTIFICATION in appropriate SELF-DIAGNOSTICS article. After each repair procedure has been completed, reconnect all components.
NOTE:
The DRBIII(R) scan tool along with the DRB Low Current Shunt (LCS) adapter and its test leads will be used to check fuel pump amperage specifications. See Fig 1
.
- Perform FUEL PRESSURE TEST , FUEL PUMP CAPACITY TEST and FUEL PRESSURE LEAK DOWN TEST before performing this test. If specifications for the Fuel Pump Pressure, Fuel Pump Capacity and Fuel Pressure Leak Down tests were met, ensure fuel tank has fuel. If fuel tank is empty or near empty, amperage readings will be incorrect. Ensure fuel tank temperature is more than 50°F (10°C).
- Be sure fuel tank contains fuel before starting test. If tank is empty or near empty, amperage readings will be incorrect.
- Obtain DRBIII(R) Low Current Shunt (LCS) adapter. See Fig 1 . Plug cable from LCS adapter into DRBIII(R) scan tool at SET 1 receptacle.
- Plug DRBIII(R) into Data Link Connector (DLC). DLC is located below instrument panel, near steering column. Connect (-) and (+) test cable leads into LCS adapter receptacles.
- Use 10-amp (l0A+) receptacle and common (-) receptacles. Gain access to MAIN MENU on DRBIII(R) screen. Press DVOM button on DRBIII(R). Using left/right arrow keys, highlight CHANNEL 1 function on DRBIII(R) screen.
- Press ENTER 3 times. Using up/down arrow keys, highlight RANGE on DRBIII(R) screen (screen will default to 2-amp scale).
- 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). Remove cover from Power Distribution Center (PDC). PDC is located in engine compartment. Remove fuel pump relay from PDC.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 relay 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.
- Attach test leads from LCS adapter into fuel pump relay cavities No. 30 and 87 in PDC (Grand Cherokee and Liberty) or cavities C9 and C10 in PDC (Wrangler).
- When LCS adapter test leads are attached into relay cavities, fuel pump will be activated. Determine fuel pump amperage on DRBIII(R) screen. Amperage should be below 10.0 amps. If amperage is below 10.0 amps, and specifications for the Fuel Pump Pressure, Fuel Pump Capacity and Fuel Pressure Leak Down tests were met, the fuel pump module is okay.
- If amperage is more than 10.0 amps, replace fuel pump module assembly. The electric fuel pump is not serviced separately. See FUEL PUMP MODULE under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION article.
- Disconnect test leads from relay cavities immediately after testing.
CAUTION:
To prevent possible damage to the vehicle electrical system and LCS adapter, the test leads must be connected into relay cavities exactly as indicated in the following steps.