0389358 JOHNSON HYDRAULIC ASSY., Power tilt and trim

Table 1
Relationship Between the Sensor's Resistance and the Voltage on the Signal Wire    
Fuel Level     Resistance     Approximate Voltage on the Signal Wire    
Full     33 Ohms     0.15 VDC    
Empty     240 Ohms     1.8 VDC    If the voltage on the signal wire falls below 0.15 VDC, a 96-04 diagnostic code is activated. If the voltage on the signal wire rises above 1.8 VDC, a 96-03 diagnostic code is activated. There is an eight second delay before either code is activated.A diagnostic code is probably caused by a problem in a wiring harness. The next likely cause is a problem with the fuel level sensor. The least likely cause is a problem with the ECM.
Illustration 1 g01129074
Schematic for the fuel level sensorTest Step 1. Inspect the Electrical Connectors and the Wiring
Turn the keyswitch to the OFF position.
Illustration 2 g01130312
Engine components for the fuel level sensor (1) J1/P1 ECM connectors (2) J803/P803 connectors for the fuel level sensor
Thoroughly inspect connectors (1) and (2). Refer to Troubleshooting, "Electrical Connectors-Inspect" for details.
Illustration 3 g01130327
P1 terminals that are associated with the fuel level sensor (P1-3) Return (P1-15) Signal
Illustration 4 g01120369
Harness connector for the fuel level sensor (1) Signal (2) Return
Perform a 45 N (10 lb) pull test on each of the wires that are associated with the fuel level sensor.
Check the allen head screw on the ECM connectors for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
Check the harness and the wiring for abrasion and for pinch points from the fuel level sensor to the ECM.Expected Result:All connectors, pins and sockets are completely coupled and/or inserted and the harness and wiring are free of corrosion, of abrasion and of pinch points.Results:
OK - The connectors and the wiring are OK. Proceed to Test Step 2.
Not OK - There is a problem in the connectors and/or the wiring.Repair: Repair the connectors and/or the wiring. Replace parts, if necessary. Verify that the repair eliminates the problem.STOPTest Step 2. Check for Active Diagnostic Codes
Connect the Caterpillar Electronic Technician (ET) to the service tool connector. Refer to Troubleshooting, "Electronic Service Tools".
Turn the keyswitch to the ON position.
Observe the "Active Diagnostic" screen on Cat ET. Wait at least 15 seconds so that any codes may become active. Look for these codes:
96-03 Fuel Level Sensor open/short to +batt
96-04 Fuel Level Sensor short to groundExpected Result:One of the above codes is active.Results:
Active 03 code - An 03 diagnostic code is active. Proceed to Test Step 3.
Active 04 code - An 04 diagnostic code is active. Proceed to Test Step 4.
No active codes - None of the above codes are active.Repair: The problem was probably caused by a poor electrical connection. Return the engine to service.STOPTest Step 3. Check the Sensor and the Vessel's Wiring
Disconnect the J803/P803 connectors.Note: Be sure to wiggle the harness during the following measurement in order to reveal an intermittent condition.
Measure the sensor's resistance between J803-1 (Signal) and J803-2 (Return).Expected Result:The resistance measurement is less than 240 Ohms.Results:
OK - The resistance measurement is less than 240 Ohms. Record the measurement. Connect the J803/P803 connectors. The sensor's resistance is OK and the vessel's wiring is OK. Proceed to Test Step 5.
Not OK - The resistance measurement is greater than 240 Ohms.Repair: Perform the following procedure:
Disconnect the fuel level sensor from the vessel's wiring. Verify that the fuel level sensor is operating correctly. Refer to the literature that is provided by the OEM for the sensor.
If the sensor is causing the high resistance, adjust the sensor, when possible. Replace the sensor, if necessary. STOP.
If the sensor's resistance reading is correct, there is excessive resistance in the vessel's wiring between the fuel level sensor and the J803/P803 connectors. Repair the wiring. Verify that the problem is resolved.STOPTest Step 4. Check the Sensor and the Vessel's Wiring
Disconnect the J803/P803 connectors.Note: Be sure to wiggle the harness during the following measurement in order to reveal an intermittent condition.
Measure the sensor's resistance between J803-1 (Signal) and J803-2 (Return).Expected Result:The resistance measurement is greater than 33 Ohms.Results:
OK - The resistance measurement is greater than 33 Ohms. Record the measurement. Connect the J803/P803 connectors. The sensor's resistance is OK and the vessel's wiring is OK. STOP
Not OK - The resistance measurement is less than 33 Ohms. Repair: Perform the following procedure:
Disconnect the fuel level sensor from the vessel's wiring. Verify that the fuel level sensor is operating correctly. Refer to the literature that is provided by the OEM for the sensor.
If the sensor is causing the low resistance, adjust the sensor, when possible. Replace the sensor, if necessary. STOP.
If the sensor's resistance reading is correct, there is a short circuit in the vessel's wiring between the fuel level sensor and the J803/P803 connectors. Repair the wiring. Verify that the problem is resolved.STOPTest Step 5. Check the Sensor's Resistance at the ECM
Disconnect the J1/P1 connectors.Note: Be sure to wiggle the harness during the following measurement in order to reveal an intermittent condition.
Measure the resistance between P1-3 (Return) and P1-15 (Signal).Expected Result:The resistance measurement is approximately equal to the resistance measurement from the previous Test Step.Results:
OK - The resistance measurement is approximately equal to the resistance measurement from the previous Test Step. The fuel level sensor and the wiring are OK.Repair