Test Description

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

1. 1:  The Diagnostic System Check - Vehicle prompts the technician to complete some basic checks and 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. 2:  This step determines if a FTP sensor malfunction is present. The input signal of the FTP sensor should indicate atmospheric pressure with the fuel tank filler cap removed. The fuel tank pressure sensor voltage will vary with atmospheric pressure. A typical FTP reading at sea level is between 3.5-3.8 volts.
3. 4:  The FTP sensor signal circuit carries a 5 volt bias that can be measured with the DMM. If the measured voltage is near zero there is a short to ground or a faulty PCM.
4. 8:  The EVAP system diagnostic can be monitored on the scan tool under the I/M System Information selection. When the EVAP test displays a YES status, indicating that the system diagnostic is completed, check for DTC P0452 in the Last Test Failed screen of the scan tool. If there is no DTC P0452 displayed the EVAP system diagnostic has run and passed, indicating that no malfunction was present this time. DTCs MUST be cleared in order to view the Current Status of the system diagnostics being performed. Do not forget that the I/M System Information tests only indicate that the test has run, not if the test passed or failed. The Last Test Failed screen must be checked for related DTCs in order to determine the outcome of the diagnostic test involved.