Diagnostic Procedure

NOTE: Fuel tank pressure sensor is mounted on top of fuel tank.

Check the fuel tank pressure sensor connector for contact resistance and oxidation. Check connector for signs of damage and poor connection. See CHECKING WIRING & CONNECTIONS . Repair as necessary and go to next step.
Assemble connector. Remove fuel tank filler cap. Connect scan tool, start engine and read out fuel tank pressure. Tank pressure should be approximately 0 psi with cap open. If so, repair is complete. If not, go to next step.
Connect breakout box. See CONNECTING & DISCONNECTING BREAKOUT BOX .
Check ground lead between PCM terminal B4 (breakout box terminal B14) and fuel tank pressure sensor connector terminal No. 1 for an open circuit. See Figure. Repair as necessary. Go to next step.
Check signal cable between PCM terminal B31 (breakout box terminal B41) and fuel tank pressure sensor connector terminal No. 2 for an open circuit, a short to ground and a short to supply voltage. See Figure. A test screwdriver with a 3-Watt (minimum) bulb will help diagnosis for short to voltage.
Check power supply cable between PCM terminal B10 (breakout box terminal B20) and fuel tank pressure sensor connector terminal No. 3 for an open circuit, a short to ground and a short to supply voltage. See Figure. Repair as necessary and go to next step.
NOTE: With fuel tank filler cap ON and tank pressure at approximately .14 psi (1 kPa), fuel tank pressure sensor voltage is approximately 2.5 volts.
Disconnect breakout box when wiring repair is complete. Verify repair. Ignition OFF. Ensure all components and connectors are installed properly. Remove fuel tank filler cap (of not already removed). Connect a scan tool and start engine. Read out fuel tank pressure. Tank pressure should be approximately 0 psi when fuel tank filler cap is open. If so, repair is complete.