Circuit Description
The PCM uses a fuel level input in order to calculate the expected vapor pressures within the fuel system. These vapor pressure vary as the fuel level changes. The vapor pressure is critical in determining if the evaporative emission (EVAP) 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 an EVAP system malfunction.
Conditions for Running the DTC
| • | The ignition is ON. |
| • | The system voltage is between 11 and 16 volts. |
Conditions for Setting the DTC
Fuel level sensor reading is less than 3.5 percent for greater than 25 seconds.
Action Taken When the DTC Sets
| • | The PCM will record the operating conditions during the time which the diagnostic fails. This information will store in the Failure Records buffer. |
| • | A history DTC is stored. |
Conditions for Clearing the DTC
| • | A history DTC clears after 40 consecutive warm up cycles without a fault. |
| • | Use a scan tool to clear the DTCs. |
Diagnostic Aids
| • | Inspect for the following conditions that may cause intermittents: |
| - | Poor electrical connections |
| - | Rubbed through wire insulation |
| - | A wire that is broken inside the wire insulation |
| • | Thoroughly inspect any circuitry that is suspected as causing the intermittent complaint. Inspect for the following conditions: |
| - | Backed out terminals |
| - | Improper mating |
| - | Broken locks |
| - | Improperly formed or damaged terminals |
| - | Poor terminal to wire connections |
| • | Before replacing the PCM, inspect the PCM electrical connector terminals for the following conditions: |
| - | Improper mating |
| - | Broken locks |
| - | Physical damage to the wiring harness |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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The Powertrain OBD System Check prompts you to complete some of the 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 captured when the malfunction occurred. The scan tool stores this data for later reference.
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This step simulates a DTC P0463. If the PCM senses the change, then the PCM and the Fuel Level Sensor wiring are OK.
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Replacement PCMs must be reprogrammed and the crankshaft position system variation procedure must be performed. Refer to the latest Techline information for programming procedures.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | |||
2 |
Is the fuel level sensor value greater than the specified value? | 3.5% | Go to Diagnostic Aids | |
Is the fuel level sensor value greater than the specified level? | 98% | |||
4 |
Was a repair necessary? | -- | ||
5 |
Is the action complete? | -- | -- | |
Important: The replacement PCM must be programmed. Did you complete the repair? | -- | -- | ||
7 |
Does the scan tool indicate that this diagnostic has ran and passed? | -- | ||
8 | Determine if any additional DTCs are set. Does the scan tool display any DTCs that have not been diagnosed? | -- | Go to applicable DTC table | System OK |
