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% or less than 15% full. (This sensor signal disables the misfire when the fuel levels are less than 15%). This DTC is a type D DTC.
Conditions for Setting the DTC
| • | The fuel tank level slosh test is completed |
| • | The tank level main test is completed |
| • | The fuel tank level data is valid |
| • | The fuel level signal is unchanged over a distance of 200 miles |
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
Number(s) below refer to the step number(s) on the diagnostic table.
-
This step determines if the problem is a VCM problem or a wiring problem.
-
This step determines if the fuel gauge and the fuel level sender module are operating correctly.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 |
Important: Before clearing the DTCs, use the scan tool in order to record the Freeze Frame and the Failure Records for reference. This data will be lost when the Clear Info function is used. Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | ||
2 |
Are the readings approximately the same? | -- | ||
Did the vehicle fuel gauge reading change? | -- | |||
4 | Check for a short to ground between the VCM and the splice. Was a problem found? | -- | Go to Engine Electrical for Fuel Gauge Diagnosis | |
5 |
Is the voltage displayed greater than the specified value? | 1.0V | ||
6 | Repair the open in the fuel level sensor signal circuit between the VCM and the splice. Is the action complete? | -- | -- | |
7 | Check the terminal contact at the VCM for the fuel level sensor signal circuit. Was a problem found? | -- | ||
8 | Repair as necessary. Is the action complete? | -- | -- | |
9 | Replace the VCM. Important: When replacing the VCM, the new VCM will need to be programmed. Refer to VCM Replacement/Programming | -- | -- | |
10 |
Does the scan tool indicate that this diagnostic ran and passed? | -- | ||
11 | Use the scan tool in order to display the Capture Info and the Review Info. Are there any DTCs displayed that have not been diagnosed? | -- | Go to Step Applicable DTC Table | System OK |
