P0461-FUEL LEVEL SENSOR 1 PERFORMANCE





For a complete wiring diagram Refer to Section 8W

Theory of Operation


Vehicles with saddle fuel tank configurations have two fuel level sending units. The primary side of the tank has the filler tube inlet near the bottom and contains the fuel pump module. During fuel tank fills, fuel must overflow the primary side to reach the secondary side. As fuel is consumed, a siphon tube is used to draw fuel from the secondary side to the primary side. Because the siphon tube flow rate exceeds the fuel consumption rate, the secondary side of the tank will be empty before fuel is depleted from the primary side. The rationality for each fuel level sensor is based on the float position of the opposite side of the tank. The primary sensor rationality is enabled when the secondary level is near the bottom of the tank. The secondary sensor rationality is enabled before the primary side begins to show fuel consumption or fuel volume is greater than a calibrated volume.


  • When Monitored:

    With engine run time greater than 128 seconds.

  • Set Condition:

    The PCM detects no change in Fuel Level Sensor 1 circuit voltage over time during monitoring.


Possible Causes
 
INTERMITTENT DTC
 
FUEL PUMP MODULE WIRING OR CONNECTORS
 
INTERIOR OR EXTERIOR FUEL TANK DAMAGE
 
(N4) FUEL LEVEL SIGNAL 1 CIRCUIT SHORTED TO VOLTAGE
 
(N4) FUEL LEVEL SIGNAL 1 CIRCUIT SHORTED TO GROUND
 
(N4) FUEL LEVEL SIGNAL 1 CIRCUIT OPEN OR HIGH RESISTANCE
 
(N5) FUEL LEVEL SIGNAL 2 CIRCUIT SHORTED TO VOLTAGE
 
(N5) FUEL LEVEL SIGNAL 2 CIRCUIT SHORTED TO GROUND
 
(N5) FUEL LEVEL SIGNAL 2 CIRCUIT OPEN OR HIGH RESISTANCE
 
(Z965) GROUND CIRCUIT OPEN OR HIGH RESISTANCE
 
(Z912) GROUND CIRCUIT OPEN OR HIGH RESISTANCE
 
FUEL LEVEL SENSOR 1
 
FUEL LEVEL SENSOR 2
 
INSTRUMENT CLUSTER (CCN)
 


Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - STANDARD PROCEDURE)



Diagnostic Test

1.DTC IS ACTIVE




Is the good trip counter greater than 0?

Yes


No
  • Go to 2

2.EXTERIOR FUEL TANK DAMAGE



Were any problems found?

Yes
  • Replace the fuel tank as necessary.
  • Perform the Body Verification Test Ver. 1 (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES)


No
  • Go to 3

3.FUEL PUMP MODULE WIRING AND CONNECTORS






Were any problems found?

Yes
  • Repair as necessary.
  • Perform the Body Verification Test Ver. 1 (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES)


No
  • Go to 4

4.(N4) FUEL LEVEL SIGNAL 1 CIRCUIT VOLTAGE







NOTE: The sensor voltage should be approximately 5.0 volts (plus or minus .1 volt) with connector disconnected.






NOTE: The sensor voltage should be approximately 0.0 volts (plus or minus .1 volt) with the jumper wire in place.



Does the scan tool display the voltage as described above?

Yes
  • Go to 5


No

5.(N5) FUEL LEVEL SIGNAL 2 CIRCUIT VOLTAGE




NOTE: The sensor voltage should be approximately 5.0 volts (plus or minus .1 volt) with connector disconnected.






NOTE: The sensor voltage should be approximately 0.0 volts (plus or minus .1 volt) with the jumper wire in place.



Does the scan tool display the voltage as described above?

Yes
  • Go to 6


No

6.(Z965) GROUND CIRCUIT OPEN OR HIGH RESISTANCE






Is the resistance below 5.0 ohms?

Yes
  • Go to 7


No
  • Repair the (Z965) Ground for an open circuit or high resistance.
  • Perform the Body Verification Test Ver. 1 (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES)

7.FUEL TANK WIRING HARNESS INSPECTION

WARNING: The fuel system is under a constant pressure (even with the engine off). Before testing or servicing any fuel system hose, fitting or line, the fuel system pressure must be released. Failure to follow these instructions can result in personal injury or death.







Were any problems found?

Yes
  • Repair as necessary.
  • Perform the Body Verification Test Ver. 1 (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES)


No
  • Go to 8

8.FUEL LEVEL SENSOR 2 INSPECTION




Were any problems found?

Yes
  • Repair or replace the fuel tank components as necessary.
  • Perform the Body Verification Test Ver. 1 (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES)


No
  • Go to 9

9.FUEL LEVEL SENSOR 2 RESISTANCE



NOTE: The resistance should be approximately 220 ohms with the float at its lowest point of travel (empty).




NOTE: The resistance should be approximately 20 ohms with the float at its highest point of travel (full).



Is the resistance of the sensor within the values described above?

Yes


No
  • Replace the Fuel Level Sensor 1.
  • Perform the Body Verification Test Ver. 1 (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES)

10.FUEL LEVEL SENSOR 1 INSPECTION




Were any problems found?

Yes
  • Repair or replace the fuel tank components as necessary.
  • Perform the Body Verification Test Ver. 1 (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES)


No
  • Replace the Fuel Level Sensor 1.
  • Perform the Body Verification Test Ver. 1 (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES)

11.(N4) FUEL LEVEL SIGNAL 1 CIRCUIT SHORTED TO VOLTAGE








Is there any voltage present?

Yes
  • Repair the (N4) Fuel Level Signal 1 circuit for a short to voltage.
  • Perform the Body Verification Test Ver. 1 (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES)


No

12.(N4) FUEL LEVEL SIGNAL 1 CIRCUIT SHORTED TO GROUND






Is the resistance above 100 ohms?

Yes


No
  • Repair the (N4) Fuel Level Signal 1 circuit for a short to ground.
  • Perform the Body Verification Test Ver. 1 (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES)

13.(N4) FUEL LEVEL SIGNAL 1 CIRCUIT OPEN OR HIGH RESISTANCE





Is the resistance below 5.0 ohms?

Yes


No
  • Repair the (N4) Fuel Level Signal 1 circuit for an open circuit or high resistance.
  • Perform the Body Verification Test Ver. 1 (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES)

14.(N5) FUEL LEVEL SIGNAL 2 CIRCUIT SHORTED TO VOLTAGE








Is there any voltage present?

Yes
  • Repair the (N5) Fuel Level Signal 2 circuit for a short to voltage.
  • Perform the Body Verification Test Ver. 1 (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES)


No

15.(N5) FUEL LEVEL SIGNAL 2 CIRCUIT SHORTED TO GROUND






Is the resistance above 100 ohms?

Yes


No
  • Repair the (N5) Fuel Level Signal 2 circuit for a short to ground.
  • Perform the Body Verification Test Ver. 1 (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES)

16.(N5) FUEL LEVEL SIGNAL 2 CIRCUIT OPEN OR HIGH RESISTANCE





Is the resistance below 5.0 ohms?

Yes


No
  • Repair the (N5) Fuel Level Signal 2 circuit for an open circuit or high resistance.
  • Perform the Body Verification Test Ver. 1 (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES)

17.INSTRUMENT CLUSTER (CCN)






Were any problems found?

Yes
  • Repair as necessary.
  • Perform the Body Verification Test Ver. 1 (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES)


No
  • Replace the Instrument Cluster (CCN) in accordance with the Service Information.
  • Perform the Body Verification Test Ver. 1 (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES)