Refer to Engine Controls Schematics
Fuel System
.
Circuit Description
The powertrain control module (PCM) uses the fuel level input in order to calculate the expected vapor pressures within the fuel system. These vapor pressures vary as the fuel level changes. The vapor pressure is critical in determining if the evaporative emissions system is operating properly. The PCM also uses the fuel level in order to determine if the fuel level is too high or too low to be able to accurately detect EVAP system malfunction.
Conditions for Running the DTC
| • | The ignition is ON. |
| • | The system voltage is between 10.0-18.0 volts. |
Conditions for Setting the DTC
The Fuel Level Sensor should be less than 3 percent for more than 10 seconds.
Action Taken When the DTC Sets
The PCM stores conditions which were present when the DTC set as Failure Records only. This information will not be stored as Freeze Frame Records.
Conditions for Clearing the MIL/DTC
| • | The DTC becomes history when the conditions for setting the DTC are no longer present. |
| • | The history DTC clears after 40 malfunction free warm-up cycles. |
| • | The PCM receives a clear code command from the scan tool. |
Important : Remove any debris from the connector surfaces before servicing a component. Inspect the connector gaskets when diagnosing or replacing a component. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion.
| • | Faulty terminal connections |
| Inspect the harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal-to-wire connections. Use a corresponding mating terminal in order to test for proper tension. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems for diagnosis and repair. |
| • | Damaged harness. |
| Inspect the wiring harness for damage. If the harness inspection does not reveal a problem, observe the display on the scan tool while moving the connectors and the wiring harnesses that are related to the sensor. A change in the scan tool display may indicate the location of the fault. Refer to Circuit Testing and Wiring Repairs in Wiring Systems for diagnosis and repair. |
| • | Inspect the PCM and the engine grounds for clean and secure connections. |
If the DTC is determined to be intermittent, reviewing the Failure Records can be useful in determining when the DTC was last set.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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The Powertrain On Board Diagnostic (OBD) System Check prompts the technician to complete some basic checks and to store the Freeze Frame and Failure Records data on the scan tool if applicable. This creates an electronic copy of the data taken when the malfunction occurred. The information is then stored in the scan tool for later reference.
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This step tests for the proper operation of the fuel level circuit in the low voltage range.
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This step tests for the proper operation of the fuel level circuit in the high voltage range. If the fuse in the jumper opens when you preform this test, the signal circuit is shorted to ground.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Did you preform the Powertrain On Board Diagnostic (OBD) System Check? | -- | |||
2 |
Important: If a 5-volt reference DTC sets, diagnosis this DTC first. Refer to DTC P1639 5 Volt Reference 2 Circuit .
Does the scan tool indicate the Fuel Level parameter is within the specified range? | 3.5%-98% | Go to Diagnostic Aids | |
Does the scan tool indicate that the fuel level parameter is less than the specified value? | 3.5% | |||
Does the scan tool indicate the fuel level parameter is more than the specified value? | 98% | -- | ||
5 | Test the fuel level signal circuit for a short to ground. Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||
6 | Replace the fuel level sensor. Refer to Fuel Level Sensor Replacement . Is the action complete? | -- | -- | |
7 |
Important : The replacement PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Is the action complete? | -- | -- | |
8 |
Does the scan tool indicate that this diagnostic ran and passed? | -- | System OK |
