Circuit Description
The Fuel Level sensor is an important input to the VCM for the Enhanced Evaporative System Diagnostic. The VCM needs the fuel level information in order to know the volume of fuel in the tank. The fuel level affects the rate of change in the air pressure in the EVAP system. Several of the Enhanced Evaporative System Diagnostic sub-test are dependent upon the correct fuel level information. The diagnostic will not run when the tank is greater than 85 percent or less than 15 percent full. (This sensor signal disables the misfire when the fuel levels are less than 15 percent). This DTC is a type C DTC.
Conditions for Running the DTC
The VCM has confirmed that the fuel tank is between 15 percent and 85 percent full.
Conditions for Setting the DTC
The fuel level sensor voltage remains below 0.39 volts for more than 20 seconds.
Action Taken When the DTC Sets
| • | The control module stores the DTC in history after the first failure but will not illuminate the malfunction indicator lamp (MIL). |
| • | The control module records the operating conditions at the time the diagnostic fails. The control module stores the failure information in the scan tools Freeze Frame/Failure Records. |
Conditions for Clearing the MIL/DTC
The VCM turns OFF the MIL after 3 consecutive driving trips without a fault condition present. A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles (the coolant temperature has risen 22°C (40°F) from the start-up coolant temperature and the engine coolant temperature exceeds 71°C (160°F) during that same ignition cycle) or the scan tool clearing feature has been used.
Diagnostic Aids
Important: Fuel level is used to determine EVAP system diagnosis. Always diagnose the fuel level sensor before any other EVAP system components or DTCs.
Do not use the fuel gauge as an indication of a shorted or open circuit as the IPC may always default to EMPTY or FULL depending upon the vehicle model.Check for the following conditions:
| • | A poor connection or damaged harness - Inspect VCM harness connectors for the following: |
| - | Backed out terminals |
| - | Improper mating |
| - | Broken locks |
| - | Poor wire to terminal connections |
| • | Intermittent test - monitor a scan tool or digital voltmeter connected between the related circuits while moving the connectors and harnesses. If the failure is induced, the voltage reading will change. This will help locate a circuit problem. |
Test Description
The numbers below refer to the step numbers in the diagnostic table.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 |
Important: Before clearing the DTCs, use the scan tool Capture Info to save the Freeze Frame and Failure Records for reference. The control module's data is deleted once the Clear Info function is used. Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||
2 |
Is the voltage less than the specified value? | 0.39V | ||
3 | This DTC is intermittent. Are any additional DTCs stored? | -- | Go to applicable DTC table | Go to Diagnostic Aids |
Is the fuel tank level sensor voltage near the specified value? | 5V | |||
5 | Check for a short to ground in the fuel level signal circuit. Was a problem found? | -- | ||
6 | Check the electrical connections at the Fuel Level Sender for corrosion or improper mating. Was a problem found? | -- | ||
7 | Repair the circuit as necessary. Refer to Wiring Repairs . Is the action complete? | -- | -- | |
8 | Replace the Fuel Level Sender. Refer to Fuel Sender Assembly Replacement . Is action complete? | -- | -- | |
9 |
Is the action complete? | -- | -- | |
10 |
Does the scan tool indicate the diagnostic Passed? | -- | ||
11 | Does the scan tool display any additional undiagnosed DTCs? | -- | Go to the applicable DTC table | System OK |
