31630-ZY3-003 Honda ALTERNATOR ASSY. (Honda Code 6991517).

Table 1
J1939 Code and Description CDL Code and Description System Response
96-3
Fuel Level : Voltage Above Normal 96-3
Fuel Level Sensor : Voltage Above Normal The code is logged.
96-4
Fuel Level : Voltage Below Normal 96-4
Fuel Level Sensor : Voltage Below Normal
96-17
Fuel Level : Low - least severe (1) N/A Add fuel to the fuel tank. Refer to the literature that is provided by the OEM of the vessel for the correct procedure. When the fuel tank is full, the fuel level sensor has a resistance of 33 Ohms. When the fuel tank is empty, the fuel level sensor has a resistance of 240 Ohms. The resistance from the fuel level sensor varies between these values as the fuel level varies.The sensors variable resistance affects the pull-up voltage that is created by the ECM. When the sensors resistance is low, the pull-up voltage is low. When the sensors resistance is high, the pull-up voltage is high. Refer to Table 2.
Table 2
Relationship Between the Sensors 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 The most likely electrical problem with the circuit for the fuel level sensor is a problem in the 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 g01379074
Schematic of the circuit that is for the fuel level sensor
Table 3
Troubleshooting Test Steps Values Results
1. Verify that the "Fuel Level Sensor Installation Status" Parameter is Programmed Correctly
A. Remove electrical power from the ECM.
B. Connect the Cat Electronic Technician (ET) to the service tool connector.
C. Restore electrical power to the ECM.
D. Establish communication with the ECM.
E. Verify that the "Fuel Level Sensor Installation Status" parameter is programmed to "Installed".
F. Remove electrical power from the ECM.
Parameter
Result: The "Fuel Level Sensor Installation Status" parameter is programmed correctly. Proceed to Test Step 2.
Result: The "Fuel Level Sensor Installation Status" parameter is programmed to "Not Installed".
Program the "Fuel Level Sensor Installation Status" parameter to "Installed". Verify that the repair eliminates the problem.
STOP
2. Inspect the Electrical Connectors and the Wiring
A. Remove the electrical power from the ECM.
B. Thoroughly inspect connectors (1) and (2). Refer to Troubleshooting, "Electrical Connectors-Inspect", for details.
C. Perform a 45 N (10 lb) pull test on each of the wires that are associated with the fuel level sensor.
D. Check the allen head screw on each of the ECM connectors for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect", for the correct torque values.
E. Check the harness and the wiring for abrasion and for pinch points from the fuel level sensor to the ECM.
Connectors
Result: The connectors and the wiring are OK. Proceed to Test Step 3.
Result: There is a problem in the connectors and/or the wiring.
Repair the connectors and/or the wiring. Replace parts, if necessary. Verify that the repair eliminates the problem.
STOP
3. Check the Resistance of the Sensor at the Harness Connector
A. Disconnect the harness connectors that are for the fuel level sensor.
B. Measure the sensors resistance between terminal 1 (fuel level) and terminal 2 (sensor return) at the sensor connector. Record the measurement.
The resistance measurement of the sensor is between 33 and 240 Ohms.
Result: The resistance measurement is between 33 and 240 Ohms. Connect the harness connectors that are for the fuel level sensor. The sensors resistance is OK. Proceed to Test Step 4.
Result: The resistance measurement of the sensor is not between 33 and 240 Ohms.
The sensor resistance is not within the specifications that are necessary for the ECM to interpret the signal. Verify that the fuel level sensor is operating correctly. Refer to the literature that is provided by the OEM for the sensor. Adjust the sensors resistance, when possible. Replace the sensor, if necessary.
STOP
4. Check the Resistance of the Sensor Through the Harness
A. Remove the wire from terminal location P1-15 for the fuel level sensor from the ECM connector to isolate the circuit.
B. Install a 7X-1709 Multimeter Probe (BLACK) into terminal location P1-03 (sensor return) at the ECM connector.
Note: Ensure that the multimeter probe is in good condition. A bent probe may contact other terminals inside the connector.
C. Measure the resistance between the loose wire and the multimeter probe at the ECM connector. Record the measurement.
Note: Be sure to wiggle the harness during the measurement to reveal an intermittent electrical condition in the harness.
The resistance measurement of the sensor through the harness is between 33 and 240 Ohms.
Result: The resistance measurement is between 33 and 240 Ohms.
The sensors resistance is OK and the vessels wiring is OK. The sensors resistance and the resistance through the wiring harness is OK. There appears to be a problem with the ECM. Replace the ECM. Refer to Troubleshooting, "ECM - Replace", for details.
STOP
Result: The resistance measurement of the sensor through the harness is not between 33 and 240 Ohms.
The resistance of the sensor at the sensor connector is within specifications. The resistance of the sensor through the harness is not within specifications. There is a problem in the wiring harness that is between the ECM connector and the sensor connector. There may be a problem with a connector. Repair the wiring, when possible. Replace parts, if necessary. Verify that the problem is resolved.
STOP