Test Description

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

1. 1  - The Diagnostic System Check - Engine Controls prompts the technician to complete some basic checks and store freeze frame data, if applicable. This creates an electronic copy of data taken when fault occurred. Information is then stored in scan tool for later reference.
2. 2  - This step determines if a FTP sensor malfunction is present. Input signal of FTP sensor should indicate atmospheric pressure with fuel tank filler cap removed. Fuel tank pressure sensor will vary with atmospheric pressure. A typical pressure at sea level is 0.0-0.5 in. H2O.
3. 3  - This step determines if DTC P0451 is the result of a hard failure or an intermittent condition. Operating vehicle in CHECK MODE enhances diagnostic capabilities of the PCM.
4. 4  - This step determines if there is trapped negative or positive pressure at FTP sensor.
5. 6  - This step inspects for an open or a short in FTP sensor 5-volt reference.
6. 7  - This step inspects for excessive resistance in reference voltage circuit. If test light does not illuminate at all, there is resistance in the circuit.
7. 9  - This step checks for an open or short in FTP sensor input circuit.
8. 11  - This step checks for an open in FTP sensor ground circuit.