Fuel Tank Pressure Sensor Operation
The Fuel Tank Pressure (FTP) sensor monitors the pressure/vacuum in the EVAP system. The EVAP system relies on this sensor for leak and component testing. It is a 3-wire sensor that has a 5-volt reference circuit, ground circuit and signal circuit. As the pressure/vacuum changes in the system, the sensor reacts and changes the voltage on the signal circuit supplied to the engine control module
Fuel Tank Pressure Sensor Test
- Check sensor inputs
- Unplug sensor connector and turn the key-on with the engine off, check for a good 5-volt reference and ground on the appropriate connector pins.
- With sensor plugged in, turn the key on and engine off, using a full functional scan tool check the FTP sensor voltage for correct reading at atmospheric pressure. (See pressure reference chart)
- If a scan tool is unavailable back probe the signal wire and use a multimeter to read sensor output voltage
- While monitoring FTP sensor voltage activate purge solenoid with a scan tool or jumper wire and check for a small change(50-500mv) in the signal. This will test the sensor's ability to change voltage and confirm it is not stuck.