Diagnostic Method

Calculate the Max. value (DELFLMAX) and cumulative value (SUMFL) of output voltage variation of fuel level sensor during 12.2 seconds. Judge it normal when both max. and cumulative values are not over the threshold value. Otherwise, when either of them is over the threshold value, the diagnosis counter counts up. Judge as NG if the counter indicated 4 time(s).

Fig 1: Fuel Level Sensor Output Voltage Graph

Courtesy of SUBARU OF AMERICA, INC.

• Abnormality Judgment 

  If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.

  Judgment Value 

  JUDGMENT VALUE REFERENCE CHART
  
  

  Malfunction Criteria	Threshold Value
  Integrated times of the condition reaching follows,	≥ 4 time(s)
  DELFLMAX or	≥ Value from Map
  SUMFL At this time, DELFLMAX: Maximum difference of sensor output for 12288 ms SUMFL: Integrated value of the sensor output deviation for 12288 ms	≥ 25.92 V

  Map 

  FUEL LEVEL SPECIFICATION CHART
  
  

  Fuel level (l  , US gal, lmp gal)	0, 0, 0	10, 2.64, 2.2	20, 5.28, 4.4	30, 7.93, 6.6	40, 10.57, 8.8	50, 13.21, 11	60, 15.85, 13.2
  Measured voltage (V)	0.27	0.27	0.426	0.582	0.738	0.894	0.894

  The diagnosis counter does not count up when the following conditions are completed within 12288 ms.

  VALUE SPECIFICATION CHART
  
  

  Maximum value - minimum value of change of tank pressure during 12288 ms	≥ 0 kPa (0.375 mmHg, 0 inHg)
  Maximum value - minimum value of battery voltage during 12288 ms	≥ 0.969 V

  Time Needed for Diagnosis:  12288 ms x 4 time(s)

  Malfunction Indicator Light Illumination:  Illuminates when malfunction occurs in 2 continuous driving cycles.

• Normality Judgment 

  Judge as OK and clear the NG if the continuous time while the following conditions are established is more than the predetermined time.

  Judgment Value 

  JUDGMENT VALUE REFERENCE CHART
  
  

  Malfunction Criteria	Threshold Value
  DELFLMAX	< Value from Map
  SUMFL At this time, DELFLMAX: Maximum difference of sensor output for 12288 ms SUMFL: Integrated value of the sensor output deviation for 12288 ms	< 25.92 V

  Time Needed for Diagnosis:  12288 ms