0343935 JOHNSON CLAMP, Fuel pump

Illustration 1 g00727703
Test Step 1. Inspect Electrical Connectors and Wiring
Turn the keyswitch to the OFF/RESET position.
Thoroughly inspect ECM connector J1/P1 and all other connectors in the wiring harness. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.Expected Result:All connectors, pins, and sockets should be completely inserted and coupled. The harness and wiring should be free of corrosion, abrasion, and pinch points. All connections and grounds should be tight and free of corrosion.Results:
OK - Proceed to Test Step 2.
Not OK - Repair: Repair the circuit.Verify that the repair eliminates the problem.STOPTest Step 2. Use ET to Check the Circuit for the Cooling Fan Solenoid
Turn the keyswitch ON.
Access the "Overrides" screen on ET.
Use the "Engine Cooling Fan Bypass Sol Override" to cycle the cooling fan on and off. When the cooling fan is turned on, the cooling fan solenoid should emit an audible click. The cooling fan should run at low speed.Expected Result:The solenoid emits an audible click and the cooling fan runs at low speed.Results:
OK - Proceed to Test Step 3.
Not OK - There is a problem in the circuit for the fan control solenoid.Repair: Repair the circuit.STOPTest Step 3. Check the Resistance through the Solenoid
Disconnect the connector for the fan control solenoid (J508/P508).
Measure the resistance between J41:1 (Fan Control Solenoid) and J41:2 (Solenoid Return).Expected Result:Resistance should be 42.0 Ohms 4.2 Ohms.Results:
OK - Proceed to Test Step 5.
Not OK - There may be a problem with the fan control solenoid. Proceed to Test Step 4.Test Step 4. Temporarily Install a New Fan Control Solenoid
Remove the fan control solenoid.
Temporarily install a new fan control solenoid.
Start the engine. Ensure that the keyswitch is in the ON position.
Access the "Overides" screen on ET.
Use the "Engine Cooling Fan Bypass Sol Override" to cycle the cooling fan on and off. When the cooling fan is turned on, the cooling fan solenoid should emit an audible click. The cooling fan should run at low speed.Expected Result:The solenoid emits an audible click and the cooling fan starts to turn at low speed.Results:
OK - The fan control solenoid was faulty.Repair: Permanently install the new fan control solenoid.Verify that the repair eliminates the problem.STOP
Not OK - There may be a problem with the harness. Proceed to Test Step 5.Test Step 5. Check for Shorts in the Harness
Illustration 2 g00727777
ECM connector P1
Disconnect ECM connector J1/P1.
Disconnect the connector for the fan control solenoid (J508/P508).
Measure the resistance between P1:19 (Fan Control Solenoid) and chassis ground.
Measure the resistance between P1:5 (Solenoid Return) and chassis ground.
Measure the resistance between P1:19 (Fan Control Solenoid) and P1:5 (Solenoid Return).Expected Result:The resistance for each measurement should be greater than 20,000 Ohms.Results:
OK - Proceed to Test Step 6.
Not OK - There is a short between the ECM and the fan control solenoid.Repair: Repair the circuit.STOPTest Step 6. Check for Open Circuits in the Harness
Illustration 3 g00727782
J1/P1 breakout
Turn the keyswitch to the OFF/RESET position and install a 70 Pin Breakout at ECM connector J1/P1.
Use a suitable piece of wire to short P1:19 (Fan Control Solenoid) and P1:5 (Solenoid Return) at the breakout.
Disconnect the connector for the fan control solenoid (J508/P508).
Measure the resistance between P508:1 (Fan Control Solenoid) and P508:2 (Solenoid Return).Expected Result:The resistance should be less than 10 Ohms.Results:
OK - The system is functioning correctly.Repair: Refer to Troubleshooting, "Electrical Connectors - Inspect" if the problem is intermittent.STOP
Not OK - There is an open circuit in the wiring harness between the fan control solenoid and the ECM.Repair: Repair the circuit.Verify that the repair eliminates the problem.STOP