Test Description

The numbers below refer to the step numbers in the diagnostic table.

1. 1:  The Diagnostic System Check-Engine Controls prompts the technician to complete some basic checks and to store the Freeze Frame data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.
2. 3:  In order to locate the C401 connector, follow the fuel tank wire harness to the square pass-through grommet located in the frame rail below the left taillight assembly. Gently pull the grommet and the harness out of the frame rail. The C401 connector is located a couple of inches from the pass-through grommet.
3. 7:  This step checks the circuit from the fuel level sensor to the PCM. Because the scan tool will display a default value of 100 percent all the time when a fuel level sensor circuit DTC is present, any current or stored fuel level sensor circuit DTCs (DTC P0463 or P0461) must be cleared before reading the fuel level parameter on the scan tool.
4. 8:  Checks for a faulty fuel level sensor.
5. 12:  This step checks for an open in the fuel level sensor signal circuit from the instrument panel cluster fuel gage to S258 only. If there is an open in the fuel level sensor signal circuit between S258 and the fuel level sensor, the PCM may see a high voltage signal and set DTC P0463 instead of P0461.
6. 14:  Clearing the DTCs by removing the DOME fuse also clears the PCM long term memory. Using the scan tool to clear DTCs leaves the long term memory active. DTC emitting diagnostics may not run to completion as expected unless the long term memory is cleared. Removal of the DOME fuse also clears the time display of the radio. The DTC P0464 diagnostic can be monitored on the scan tool under the Not Ran Since Code Cleared selection in the DTC Information menu. If a DTC P0464 appears in the Not Ran Since Code Cleared list, the DTC P0464 diagnostic has not yet run. When the DTC P0464 does not appear in the Not Ran Since Code Cleared list, the DTC P0464 diagnostic has run. If the MIL is NOT illuminated, and there is no Pending DTC Status in DTC Information, the DTC P0464 diagnostic has passed. The DTCs MUST be cleared in order to view the Current Status of the Not Ran Since Code Cleared list. DO NOT forget that the Not Ran Since Code Cleared list only indicates that the test has run, not whether the test passed or failed. The DTC Information screen must be checked for Current or Pending status, in order to determine the outcome of the diagnostic test involved.
7. 15:  This step checks whether the malfunction that caused the DTC P0461 is still present. Driving the vehicle under these conditions will verify whether the fault is present. After performing the scan tool Clear DTC Information function, the DTC P0461 diagnostic can be monitored on the scan tool under the Not Ran Since Code Cleared selection in the DTC Information menu. If DTC P0464 appears in the Not Ran Since Code Cleared list, the P0464 diagnostic has not yet run. When DTC P0464 does not appear in the Not Ran Since Code Cleared list, the P0464 diagnostic has run. If the MIL is NOT illuminated and there is no Pending DTC Status in DTC Information, the P0464 diagnostic has passed. The DTCs MUST be cleared in order to view the Current Status of the Not Ran Since Code Cleared list. DO NOT forget that the Not Ran Since Code Cleared list only indicates that the test has run, not whether the test passed or failed. The DTC Information screen must be checked for Current or Pending status in order to determine the outcome of the diagnostic test involved.