Emission Control: Overview Scion tC I

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1. INSPECT AIR-FUEL RATIO COMPENSATION SYSTEM Measure the voltage between the terminals of the ECM connectors. Standard: TERMINALS VOLTAGE SPECIFICATIONS Tester Connection Condition Specified Condition B2-23 (A1A+) - B1-1 (E1) Ignition switch ON 3.3 V B2-31 (A1A-) - B1-1 (E1) Ignition switch ON 2.9 V NOTE: Connect test leads from the back side of the connector. The connectors should not be disconnected from the ECM. HINT: The voltage between the terminals of the ECM is kept constant regardless of the voltage of the A/F sensor. Connect the hand-held tester to the DLC3. Turn the ignition switch to ON. Select the following menu items: Data List / A/FS B1 S1 and O2S B1 S2. Warm up the A/F sensor with the engine speed at 2,500 rpm for approximately 2 minutes. Keep the engine speed at 2,500 rpm and confirm that the display of "A/FS B1 S1" is as shown in the illustration. HINT: The illustration may slightly differ from the display on the hand-held tester. Only the hand-held tester displays the waveform of the A/F sensor. Confirm that the display of "O2S B1 S2" changes between 0 and 1 V with the engine speed at 2,500 rpm. OK: The voltage output oscillates more than 8 times in 10 seconds. CAUTION: Perform the check immediately after warming the engine up. f the voltage variation could not be verified, warm up the heated oxygen sensor again. If it could not be verified even after warming up the sensor again, check the DTC No. (See «DIAGNOSTIC TROUBLE CODE CHART»(/scion/tc/i-2004-2007/remont/testing-diagnostics/#sfi-system-2az-fe) )
2. INSPECT FUEL CUT OFF RPM Increase the engine speed to at least 3,500 rpm. Use a sound scope to check for injector operating sounds. Check that injector operating sounds stop momentarily and then resume when the throttle lever is released.
3. VISUALLY INSPECT HOSES, CONNECTIONS AND GASKETS Check the appearance. Check if the indicated portions of the engine assembly are cracked, leaking or damaged. HINT: Disconnection of the engine oil level gage, oil filler cap, PCV hose, etc. may cause the engine to run improperly. Disconnection, looseness or cracks in the parts of the air induction system between the throttle body and cylinder head will allow air suction and cause the engine to run improperly. If necessary, repair the engine assembly.
4. INSPECT EVAP SYSTEM LINE Warm up the engine and stop the engine. Warm up the engine to normal operating temperature. Install a vacuum gauge (EVAP control system test equipment vacuum gauge) into the EVAP service port on the purge line. When using a hand-held tester: Operation of VSV of EVAP using hand-held tester. Connect the hand-held tester to the DLC3. Start the engine. Turn the hand-held tester ON. Select the following menu items: DIAGNOSIS / ENHANCED OBD \\l ACTIVE TEST / EVAP VSV (ALONE). When not using a hand-held tester: Operation of VSV of EVAP not using hand-held tester. Disconnect the VSV for EVAP connector. Connect the positive (+) and negative (-) leads of the battery to the VSV for EVAP terminals. Start the engine. Check the vacuum when the engine idles. Vacuum: Maintain at 0.368 to 19.713 in.Hg (5 to 268 in.Aq) for over 5 seconds. HINT: If the vacuum does not change, the hose connecting the VSV to the service port is loose or blocked, or the VSV is malfunctioning. When using a hand-held tester: Conclude operation of VSV of EVAP using hand-held tester. Stop the engine. Disconnect the hand-held tester from the DLC3. When not using a hand-held tester: Conclude operation of VSV of EVAP not using hand-held tester. Stop the engine. Disconnect the positive (+) and negative (-) leads of the battery from the VSV for EVAP terminals. Connect the VSV for EVAP connector. Disconnect the vacuum gauge from the EVAP service port on the purge line. Connect a pressure gauge to the EVAP service port on the purge line. Check the pressure. Prepare a rubber hose that has an inside diameters of 15 to 18.5 mm. Disconnect the atmospheric side hose of the pump module. Connect the prepared rubber hose to the pump module, and pinch the rubber hose with the clip to prevent air from entering into the canister passage. Apply pressure (13.5 to 15.5 in.Aq) from the EVAP service port. Pressure: The gauge should still read over 7.7 to 8.8 in.Aq for 2 minutes after the pressure is applied. HINT: If you cannot apply pressure, the hose connecting the VSV, charcoal canister and fuel tank has slipped off or the VSV is open. Check if the pressure decreases when the fuel tank cap is removed while applying pressure. HINT: If the pressure does not decrease when the filler cap is removed, the hose connecting the service port to the fuel tank is blocked, etc. Disconnect the pressure gauge from the EVAP service port on the purge line.
5. INSPECT FUEL CUTOFF VALVE AND FILL CHECK VALVE Disconnect the vent line hose from the fuel tank (See «REMOVAL & INSTALLATION AND DISASSEMBLY & REASSEMBLY»(ref-224766-S14470383222006031100000) ). Connect the pressure gauge to the fuel tank. Fill the fuel tank with fuel. Apply pressure of 4 kPa (41 gf/cm 2, 0.58 psi) to the vent port of the fuel tank. HINT: It is necessary to check the amount of fuel in the fuel tank. When the fuel tank is full, the float valve of the fill check valve is closed and no air can pass through. Remove the fuel tank cap, and check that pressure drops. If the pressure does not drop, replace the fuel tank assembly. Reconnect the vent line hose to the fuel tank.
6. CHECK AIR INLET LINE Disconnect the air inlet line hose from the charcoal canister. Check that air can flow freely into the air inlet line. If air cannot flow freely into the air inlet line, repair or replace it. Reconnect the air inlet line hose to the charcoal canister.
7. INSPECT LEAK DETECTION PUMP (PRESSURE SENSOR) Measure the power source voltage of the ECM connectors. Standard: ECM CONNECTORS TERMINALS VOLTAGE SPECIFICATIONS Tester Connection Condition Specified Condition B3-18 (VC) - B3-28 (E2) Ignition switch ON 4.5 to 5.5 V If the voltage is not as specified, check the ECM, leak detection pump and wire harness. Measure the power output of the ECM connectors. Remove the fuel tank cap. Standard: ECM TERMINALS VOLTAGE SPECIFICATIONS Tester Connection Condition Specified Condition C2-21 (PPMP) - B3-28 (E2) Ignition switch ON 1.425 to 4.150 V If the voltage is not as specified, check the ECM, leak detection pump and wire harness. Install the fuel tank cap.

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1. INSPECT VENTILATION VALVE SUB-ASSY Check the operation. Install a clean hose as shown onto valve. Blow air into the cylinder head side and check that the air passes through easily. CAUTION: Do not suck air through the ventilation valve. Petroleum substances inside the ventilation valve are harmful. Blow air into the intake manifold side and check that the air does not pass through freely. If the operation is not as specified, replace the ventilation valve.
2. INSPECT FUEL TANK CAP ASSY Check the appearance. Visually check whether the fuel tank cap and gasket are deformed or damaged. If necessary, repair or replace the cap and/or gasket.
3. INSPECT CHARCOAL CANISTER ASSY Visually check the charcoal canister for cracks or damage. If cracks or damage are found, replace the charcoal canister assy. Check charcoal canister operation. While holding the purge port closed, blow air 1.67 kPa (17.0 gf/cm 2 , 0.24 psi) to the vent port, and check that the the air flows from the air inlet port. If the result is not as specified, replace the charcoal canister assy. While holding the vent port closed, blow air to the air inlet port 1.10 kPa (11.2 gf/cm 2 , 0.16 psi) to the purge port, and check that the air flows from the purge port. If the result is not as specified, replace the charcoal canister assy. Check the air leakage. Remove the air hose between ports A and B. Connect the pressure gauge to the vent port of the charcoal canister. SST 09992-00242 While holding port B, the purge port and the air inlet port closed and port A open, apply pressurized air 19.6 kPa (0.2 kgf/cm 2 , 2.81 psi) to the vent port, then confirm that the pressure is retained. If the result is not as specified, replace the charcoal canister assy. Check leak detection pump. Check that air flows from port A to ports B and C. If the result is not as specified, replace the charcoal canister assy. Apply battery positive voltage across the terminals. Check that the valve is closed. If the result is not as specified, replace the charcoal canister assy.
4. INSPECT VACUUM SWITCHING VALVE ASSY NO.1 Check the resistance. Using an ohmmeter, measure the resistance between the terminals. Standard: TERMINALS RESISTANCE SPECIFICATIONS Tester Connection Specified Condition 1 -2 30 to 34 ohm at 20°C (68°F) If the resistance is not as specified, replace the vacuum switching valve No. 1. Check the vacuum switching valve No. 1 for ground. Using an ohmmeter, check the resistance between each terminal and the body. Standard: TERMINALS RESISTANCE SPECIFICATIONS Tester Connection Specified Condition 1 - Body 10 Mohm or higher 2 - Body 10 Mohm or higher If the resistance is not as specified, replace the vacuum switching valve No. 1. Check the operation. Check that air does not flow from port E to port F. If the operation is not as specified, replace the vacuum switching valve No. 1. Apply battery voltage across the terminals. Check that air flows from port E to port F. If the operation is not as specified, replace the vacuum switching valve No. 1.
5. INSPECT AIR FUEL RATIO SENSOR Check the resistance. (Bank 1 Sensor 1) Using an ohmmeter, measure the resistance between the terminals. Standard: TERMINALS RESISTANCE SPECIFICATIONS Tester Connection Specified Condition 1 (HT) - 2 (+B) 1.8 to 3.4 ohm at 20°C (68°F) 1 (HT) - 4 (AF-) 10 kohm or higher If the result is not as specified, replace the air fuel ratio sensor.
6. INSPECT HEATED OXYGEN SENSOR Check the resistance. (Bank 1 Sensor 2) Using an ohmmeter, measure the resistance between the terminals. Standard: TERMINALS RESISTANCE SPECIFICATIONS Tester Connection Specified Condition 1 (HT) - 2 (+B) 11 to 16 ohm at 20°C (68°F) 1 (HT) - 4 (E) 10 kohm or higher If the result is not as specified, replace the heated oxygen sensor.

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1. REMOVE ENGINE COVER SUB-ASSY NO.1 (See «REPLACEMENT»(ref-224765-S25278912682006031100000) )
2. DISCONNECT VENTILATION HOSE NO.2 Disconnect the ventilation hose No. 2 from the ventilation valve.
3. REMOVE VENTILATION VALVE SUB-ASSY Using a deep socket wrench 22 mm, remove the ventilation valve.
4. INSTALL VENTILATION VALVE SUB-ASSY Install the ventilation valve. Apply adhesive to 2 or 3 threads. Adhesive: Part No. 08833 - 00070, THREE BOND 1324 or equivalent. Using a deep socket wrench 22 mm, install the ventilation valve. Torque: 19 N.m (194 kgf.cm, 14 ft.lbf)
5. CONNECT VENTILATION HOSE NO.2 Connect the ventilation hose No. 2 to the ventilation valve. NOTE: Make sure that the paint mark and hose clamp are at the correct angle when installing.
6. CHECK FOR ENGINE OIL LEAKAGE
7. INSTALL ENGINE COVER SUB-ASSY NO.1 (See «REPLACEMENT»(ref-224765-S25278912682006031100000)

See also:
• DIAGNOSTIC TROUBLE CODE CHART
• REMOVAL & INSTALLATION AND DISASSEMBLY & REASSEMBLY