Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Test Description
2001 Chevrolet Cavalier LS, 2.4 TSECTION Test Description
WARNING: This page is about a different car, the 2003 Pontiac Vibe. However, it is still accessible from the selected car via links, so may be relevant.
The numbers below refer to the step numbers in the diagnostic procedures.
- 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 - 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 - 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 - This step determines if there is trapped negative or positive pressure at FTP sensor.
- 6 - This step inspects for an open or a short in FTP sensor 5-volt reference.
- 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.
- 9 - This step checks for an open or short in FTP sensor input circuit.
- 11 - This step checks for an open in FTP sensor ground circuit.
RENDER: 1.0x
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.