DTC P0450: Evaporative (EVAP) Control System Pressure Sensor Malfunction
- Remove fuel filler cap. Turn ignition on. On models equipped with 3-speed automatic or manual transmission, measure voltage between ground and terminal No. 1 (Brown/Red wire) at 16-pin PCM harness connector. On models equipped with 4-speed automatic transmission, measure voltage between ground and terminal No. 7 (Brown/Red wire) at 12-pin PCM harness connector. If voltage is less than 0.5 volt, go to step 4). If voltage is 0.5-4.5 volts, go to next step. If voltage is greater than 4.5 volts, go to step 6).
- Remove tank pressure sensor. Connect three 1.5 volt batteries in series. Connect positive terminal to "Vin" terminal of tank pressure sensor. See Fig 1
. Connect negative terminal to "Ground" terminal. Using DVOM, measure voltage between terminals "Vout" and "Ground". Connect a hand-held vacuum pump to tank pressure sensor. As vacuum is applied, voltage should decrease. See TANK PRESSURE SENSOR VOLTAGE
table. If voltage is as specified, go to next step. If voltage is not as specified, replace tank pressure sensor and retest system.TANK PRESSURE SENSOR VOLTAGE
Applied Vacuum: In. Hg (mm Hg) Output Voltage 0 (0) 2.00-2.75 2 (50) 0.20-0.75 - Check system for an intermittent problem. See TESTS W/O CODES article. Repair as necessary. If system is okay, replace PCM and retest system.
- Turn ignition off. Disconnect tank pressure sensor harness connector. Turn ignition on. Using DVOM, measure voltage between ground and Gray/Red wire at tank pressure sensor harness connector. If voltage is 4.75-5.25 volts, go to next step. If voltage is not as specified, check Gray/Red wire for an open or short to ground. Repair as necessary. If wire is okay, replace PCM and retest system.
- Connect three 1.5 volt batteries in series. Connect positive terminal to "Vin" terminal of tank pressure sensor. See Fig 1 . Connect negative terminal to "Ground" terminal. Using DVOM, measure voltage between terminals "Vout" and "Ground". Connect a hand-held vacuum pump to tank pressure sensor. As vacuum is applied, voltage should decrease. See TANK PRESSURE SENSOR VOLTAGE table. If voltage is not as specified, replace tank pressure sensor. If voltage is as specified, check Brown/Red wire for an open or short to ground. Repair as necessary. If wire is okay, replace PCM and retest system.
- Turn ignition off. Disconnect tank pressure sensor harness connector. Turn ignition on. Using DVOM, measure voltage between ground and Gray/Red wire at tank pressure sensor harness connector. If voltage is 4.75-5.25 volts, go to next step. If voltage is not as specified, check Gray/Red wire for a short to power. Repair as necessary. If wire is okay, replace PCM and retest system.
- Connect three 1.5 volt batteries in series. Connect positive terminal to "Vin" terminal of tank pressure sensor. See Fig 1 . Connect negative terminal to "Ground" terminal. Using DVOM, measure voltage between terminals "Vout" and "Ground". Connect a hand-held vacuum pump to tank pressure sensor. As vacuum is applied, voltage should decrease. See TANK PRESSURE SENSOR VOLTAGE table. If voltage is not as specified, replace tank pressure sensor. If voltage is as specified, check Gray/Red wire for a short to Brown/Red wire, or an open in Gray/Yellow wire. Repair as necessary. If wires are okay, replace PCM and retest system.