EVAP Canister Shutoff Solenoid Valve
EVAP canister shutoff solenoid valve is located at right front side of engine compartment, accessed through the wheel well.
EVAP canister shutoff solenoid valve connects to EVAP canister air inlet hose and is powered by the main relay. The valve is grounded via ECM pin 28. The valve is normally open when engine is in closed loop operation. The valve is closed only during fuel tank integrity diagnostic check.
- Raise vehicle and remove right front wheel.
- Remove mud flap.
- Remove wheel well liner by loosening rivets center pin with a drift.
- Remove front wheel well-to-air shield and bumper retaining screws.
- Carefully disconnect wing arch liner snap fasteners with a screwdriver.
- Carefully remove wing arch liner without damaging paintwork.
- Remove shutoff valve.
Reverse removal procedure. Tighten wheel lug nuts to 80 ft. lbs. (110 Nm).
Check EVAP canister shutoff valve resistance with the ignition OFF. Connect an ohmmeter across the shutoff valve-s two terminals. Resistance should be 22 to 28 ohms at 68°F (20°C). DTC P0455 is set when a major leak is present.
EVAP Purge Control Valve
The EVAP canister, which is filled with activated charcoal, temporarily stores vapors from fuel tank and releases them through EVAP purge valve into intake manifold for combustion. The EVAP canister purge valve is a solenoid connected by vacuum hoses between EVAP canister and intake manifold. The valve is closed when not supplied with electrical current. The Trionic system main relay supplies EVAP valve with current controlled by ECM pin 27. EVAP valve is supplied with a pulse width modulation frequency of 8 Hz during closed loop operation, when engine coolant temperature is above 140°F (60°C) and intake manifold pressure is below 13 psi (90 kPa). The ECM begins purging fuel vapor with very short pulses, gradually increasing pulse duration as closed loop operation continues and additional fuel enters the system. The canister purge valve operates for 4 1 / 2 minutes, stops for 30 seconds, and then repeats.Removal & Installation
See Figure 21.
Disconnect wiring connector from purge valve. Disconnect purge valve vacuum hoses. Remove purge valve from its round bracket.
Reverse removal procedure and ensure valve is in correct position.
See Figure 22.
- Check that the canister purge valve makes a clicking sound during closed loop operation. If no sound is heard and DTC codes P0443, P0444 or P0445 are set, check for intermittent wiring faults while wiggling the wiring harness and connectors while observing a voltmeter.
- Check the resistance of the EVAP canister purge valve. With the ignition OFF, disconnect the valve-s two-pin wiring connector. Using an ohmmeter, measure across the valve-s connector pins. The correct reading is 23 to 29 ohms. If it is not, replace the valve.
- Check the purge valve-s power supply with the engine idling. Connect a test lamp between purge valve female connector pin 1 and ground. Test lamp should light up. If not, repair or replace the wiring lead between connector pin 1 and crimped connection J67.
- Check for purge valve ground connection fault. With ohmmeter connected between purge valve connector pin 2 and ECM pins 21 and 27, reading should be less than 1 ohm.
- Use an appropriate scan tool to activate purge valve for 10 seconds with 8 Hz at 50 percent. Check for clicking sound, indicating activation.
Fuel Tank Pressure Sensor
Fuel tank pressure sensor checks EVAP system pressure and is used only during OBD II tank integrity test. A partial vacuum is created and maintained in the system for a set time during the diagnostic process. A diagnostic trouble code (P0452 or P0453) is set when two negative results have been obtained during the same driving cycle.
If there is leakage during one of the tests, instrument panel will display -TIGHTEN FUEL FILLER CAP-. This message is sent after each test if leakage is detected, but not more than twice in succession. After this, it is not possible to send the message again until test diagnosis has reported OK.
Fuel tank pressure sensor connects to fuel tank filler pipe with a short hose. ECM pin 42 delivers 5 volts of power to fuel tank pressure sensor. ECM pin 67 grounds the pressure sensor.
Pressure sensor delivers a voltage to ECM pin 21 that is proportional to difference between fuel tank pressure and atmospheric pressure. When there is no difference in pressure between fuel tank and atmosphere, pressure sensor voltage is 2.5 volts.Removal & Installation
- Raise vehicle and remove right rear wheel.
- Clean around filler pipe to prevent dirt from entering fuel tank.
- Remove plastic screw securing filler pipe to vehicle body.
- Remove hose clips and plastic hose connecting filler pipe to fixed tank pipe.
- Disconnect fuel tank pressure sensor wiring connector.
- Lower vehicle to floor.
- Grip filler pipe with one hand under fender and use a screwdriver to remove filler pipe from its collar at filler cap.
- Remove fuel tank pressure sensor.
- Install pressure sensor to tank.
- Connect but do not fully install plastic filler pipe.
- Raise vehicle and connect pressure sensor wiring connector.
- Connect plastic hose between filler pipe and fuel tank.
Install filler pipe to vehicle body using a new plastic screw. Tighten screw to 1.5 ft. lbs. (2 Nm).
WARNINGUse a new plastic screw to secure filler pipe to vehicle body. In case of collision, the plastic screw must give way to avoid damaging plastic filler pipe.
- Install right rear wheel and tighten lug nuts to 80 ft. lbs. (110 Nm).
If DTCs P0451, P0452 or P0453 are set, EVAP system pressure is incorrect.
- To test system power supply, turn ignition switch ON, then OFF.
- Disconnect fuel tank pressure sensor 4-pin wiring connector near filler pipe, under vehicle.
- Connect voltmeter and check for 5 volt reference signal between connector pin 1 and ground. Move wiring harness and check for intermittent faults.
- To check pressure sensor ground, connect test lamp between sensor female connector pin 2 and battery power. Test lamp should light. Move wiring harness and check for intermittent faults.
- To check sensor ECM input, turn ignition ON, connect SAAB ISAT or equivalent scan tool, and turn ignition OFF.
- Select -Tank Pressure.- Pressure should read -29 to -44 psi (-200 kPa to -300 kPa).
- Connect a jumper wire between ECM female connector pin 1 and 3. Pressure should read -29 to -44 psi (-200 kPa to -300 kPa).
- If all tests pass, exchange fuel tank pressure sensor with a known good unit, clear all DTCs and perform a drive cycle at varying engine loads and speeds for five minutes.
- Evaluate drive cycle and check that DTCs have not reoccurred.