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.
Circuit/System Description
The control module monitors the fuel tank pressure (FTP) sensor signal in order to detect vacuum decay and excess vacuum during the evaporative emission (EVAP) diagnostic test. The control module supplies a 5-volt reference and a low reference circuit to the FTP sensor. This DTC sets if the engine control module (ECM) detects one of the following conditions:
- The FTP sensor signal voltage is not within a calibrated range on a cold start-up.
- The FTP sensor signal oscillates greater than a calibrated amount when vehicle speed is less than 30 km/h (50 mph).
The following table illustrates the relationship between FTP sensor signal voltage and the EVAP system pressure/vacuum.
| FTP Sensor Signal Voltage | Fuel Tank Pressure |
|---|---|
| High, Approximately 1.5 Volts or greater | Negative Pressure/Vacuum |
| Low, Approximately 1.5 Volts or Less | Positive Pressure |
NO RELATED
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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.