2007 Liberty KJ Factory Service Manual 8 - ELECTRICAL

*FUEL GAUGE INACCURATE

For a complete wiring diagram Refer to Section 8W.



Possible Causes
  
FUEL LEVEL SENSOR DTC PRESENT
  
INTERMITTENT CONDITION
  
FUEL LEVEL SENSOR
  
INSTRUMENT CLUSTER
  



Diagnostic Test

1. FUEL LEVEL SENSOR DTC PRESENT

NOTE: Diagnose and repair any PCM Fuel Level DTCs before proceeding with this test.


With the scan tool, read DTCs.

Does the scan tool display any Fuel Level Sensor DTCs?

Yes


No

2. INSTRUMENT CLUSTER

Perform the Instrument Cluster Self Test.
Depress and hold the Trip Odometer reset button while turning the ignition on.

NOTE: The Instrument Cluster Self Test can also be performed using the scan tool.


Observe the Fuel Gauge calibration points during the Self Test.
The Fuel Gauge indicator needle should pause at the following positions:
Off: Empty Stop below "E"
Calibration Point 1: "1/4"
Calibration Point 2: "1/2"
Calibration Point 3: "F"
Calibration Point 4: "3/4"
Calibration Point 5: "1/2"
Calibration Point 6: "1/4"
Calibration Point 7: "E"

Did the Fuel Gauge needle pause at the correct calibration points?

Yes


No

3. FUEL LEVEL SENSOR

With the scan tool, select Body, MIC, then Monitors.
Read the Fuel Tank Level Volts.
Compare the Fuel Tank Level Volts displayed by the scan tool to the Fuel Gauge using the following values:
4.3 - 3.19 Volts (Approximately 220 - 200 Ohms of Fuel Sensor Resistance) = "E"
2.56 Volts (Approximately 160 Ohms of Fuel Sensor Resistance) = "1/4"
1.91 Volts (Approximately 120 Ohms of Fuel Sensor Resistance) = "1/2"
1.27 Volts (Approximately 80 Ohms of Fuel Sensor Resistance) = "3/4"
0.319 - .646 Volts (Approximately 20 - 40 Ohms of Fuel Sensor Resistance) = "F"

NOTE: Fuel Tank Level Voltage should be within +/- 0.2 volts.



Is the displayed Fuel Tank Level voltage correct?

Yes


No