Part 2

1GR-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P2401: Evaporative Emission System Leak Detection Pump Control Circuit Low (Continued)

16. INSPECT VACUUM SWITCHING VALVE ASSEMBLY NO.1 (PURGE VSV)

(a) Remove the purge VSV.
(b) Apply battery voltage to the terminals of the purge VSV.
(c) Using an air gun, confirm that air flows from port A to port B.
Result:

(d) Reinstall the purge VSV.
B -- REPLACE VACUUM SWITCHING VALVE ASSEMBLY NO.1 (PURGE VSV)
A -- Continue to next step.
17. CHECK HARNESS AND CONNECTOR (POWER SOURCE OF PURGE VSV)

(a) Disconnect the V4 purge VSV connector.
(b) Turn the ignition switch ON.
(c) Measure the voltage between terminal 1 of the purge VSV connector and the body ground.
Result:

(d) Reconnect the purge VSV connector.
B -- REPAIR OR REPLACE HARNESS AND CONNECTOR
A -- Continue to next step.
18. CHECK HARNESS AND CONNECTOR (PURGE VSV - ECM)

(a) Disconnect the E4 ECM connector and the V4 purge VSV connector.
(b) Check the resistance.
Standard Resistance:

(c) Reconnect the purge VSV connector.
(d) Reconnect the ECM connector.
NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- REPLACE ECM
19. PERFORM ACTIVE TEST USING TECHSTREAM (FOR VENT VALVE)

(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch ON and turn the tester ON.
(c) Enter the following menus: Powertrain / Engine and ECT / Active Test / Activate the VSV for Vent Valve.
(d) Measure the voltage between terminal VPMP of the ECM connector and the body ground when the vent valve is turned ON (close) and OFF (vent) using the tester.
Result:

B -- REPLACE ECM
A -- INSPECT CANISTER PUMP MODULE (VENT VALVE OPERATION)
20. PERFORM ACTIVE TEST USING TECHSTREAM (FOR VENT VALVE)

(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch ON and turn the tester ON.
(c) Enter the following menus: Powertrain / Engine and ECT / Activate the VSV for Vent Valve.
(d) Measure the voltage between terminal VPMP of the ECM connector and the body ground when the vent valve is turned ON (close) and OFF (vent) using the tester.
Result:

C -- REPLACE ECM
B -- INSPECT CANISTER PUMP MODULE (VENT VALVE OPERATION)
A -- Continue to next step.

21. INSPECT CANISTER PUMP MODULE (POWER SOURCE FOR VENT VALVE)

(a) Turn the ignition switch OFF.
(b) Disconnect the L1 canister connector.
(c) Turn the ignition switch ON.
(d) Measure the voltage between terminal 9 (VLVB) of the canister connector and the body ground.
Result:

(e) Reconnect the canister connector.
B -- REPAIR OR REPLACE HARNESS AND CONNECTOR
A -- Continue to next step.
22. INSPECT CANISTER PUMP MODULE (VENT VALVE OPERATION)

(a) Turn the ignition switch OFF.
(b) Disconnect the L1 canister connector.
(c) Apply the battery voltage to terminals 9 and 8 of the canister pump module.
(d) Touch the canister pump module to confirm the vent valve operation.
Result:

(e) Reconnect the canister connector.
B -- REPLACE CANISTER ASSEMBLY
A -- REPAIR OR REPLACE HARNESS AND CONNECTOR
23. PERFORM ACTIVE TEST USING TECHSTREAM (FOR CANISTER PUMP MODULE (LEAK DETECTION PUMP))

(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch ON and turn the tester ON.
(c) Enter the following menus: Powertrain / Engine and ECT / Active Test / Activate the Vacuum Pump.
(d) Measure the voltage between terminal MPMP of the ECM connector and the body ground when the leak detection pump is turned ON and OFF using the tester.
Result:

B -- REPLACE ECM
A -- Continue to next step.
24. CHECK HARNESS AND CONNECTOR (CANISTER PUMP MODULE - ECM)

(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch OFF.
(c) Disconnect the L1 canister connector.
(d) Turn the ignition switch ON and turn the tester ON.
(e) Enter the following menus: Powertrain / Engine and ECT / Active Test / Activate the Vacuum Pump.
(f) Turn the leak detection pump ON.
(g) Measure the voltage between terminal 1 (MTRB) of the canister connector and the body ground.
Result:

(h) Reconnect the canister connector.
B -- REPAIR OR REPLACE HARNESS AND CONNECTOR
A -- Continue to next step.
25. CHECK HARNESS AND CONNECTOR (CANISTER PUMP MODULE - GROUND)

(a) Disconnect the L1 canister connector.
(b) Turn the ignition switch OFF.
(c) Check the resistance between terminal 6 (MGND) of the canister connector and the body ground.
Result:

(d) Reconnect the canister connector.
B -- REPAIR OR REPLACE HARNESS AND CONNECTOR
A -- REPLACE CANISTER ASSEMBLY
26. INSPECT THROTTLE W/MOTOR BODY ASSEMBLY (EVAP PURGE PORT)
(a) Stop the engine.
(b) Disconnect the EVAP hose from the throttle body.
(c) Start the engine.
(d) Use your finger to confirm that the port of the throttle body has suction.
Result:

(e) Reconnect the EVAP hose.
B -- INSPECT THROTTLE W/MOTOR BODY ASSEMBLY
A -- REPLACE EVAP HOSE (THROTTLE BODY - PURGE VSV)
27. CORRECTLY REINSTALL OR REPLACE FUEL CAP ASSEMBLY

HINT:
- When reinstalling the fuel cap, tighten it until a few click sounds are heard.
- When replacing the fuel cap, use a fuel cap that meets OEM specifications, and install it until a few click sounds are heard.

NEXT -- PERFORM EVAP SYSTEM CHECK (AUTOMATIC MODE)
28. REPLACE FUEL CAP ASSEMBLY

HINT: When installing the fuel cap, tighten it until a few click sounds are heard.

NEXT -- PERFORM EVAP SYSTEM CHECK (AUTOMATIC MODE)
29. REPAIR LOCATE EVAP LEAK
(a) Reinstall the fuel cap.
(b) Disconnect the vent hose.

(d) Pressurize the EVAP system to 3.2 to 3.7 kPa (24 to 28 mmHg).
(e) Apply soapy water to the piping and connecting parts of the EVAP system.
(f) Look for areas where bubbles appear. This indicates leak point.
(g) Repair or replace the leak point.

HINT: Disconnect the hose between the canister and the fuel tank from the canister. Block the canister side and conduct an inspection. In this way, the fuel tank can be excluded as an area suspected of causing fuel leaks.

NEXT -- PERFORM EVAP SYSTEM CHECK (AUTOMATIC MODE)
30. REPLACE CANISTER ASSEMBLY
(a) Replace the canister assembly (Removal).

NOTE: When replacing the canister, check the canister pump module interior and related pipes for water, fuel or other liquids. If liquids are present, check for disconnections and/or cracks in the following: 1) the pipe from the air inlet port to the canister pump module: 2) the canister filter; and 3) the fuel tank vent hose.

NEXT -- PERFORM EVAP SYSTEM CHECK (AUTOMATIC MODE)
31. REPLACE VACUUM SWITCHING VALVE ASSEMBLY NO.1 (PURGE VSV)

(a) Disconnect the connector and the hoses from the purge VSV.
(b) Remove the purge VSV.
(c) Install a new purge VSV.
(d) Reconnect the connector and hoses.
NEXT -- PERFORM EVAP SYSTEM CHECK (AUTOMATIC MODE)
32. REPAIR OR REPLACE HARNESS AND CONNECTOR
NEXT -- PERFORM EVAP SYSTEM CHECK (AUTOMATIC MODE)
33. REPLACE EVAP HOSE (THROTTLE BODY - PURGE VSV)
NEXT -- PERFORM EVAP SYSTEM CHECK (AUTOMATIC MODE)
34. INSPECT THROTTLE W/MOTOR BODY ASSEMBLY
(a) Remove the throttle body (Removal).
(b) Check that the EVAP purge port of the throttle body is not clogged. If necessary, replace the throttle body.
NEXT -- PERFORM EVAP SYSTEM CHECK (AUTOMATIC MODE)
35. REPLACE ECM
(a) Replace the ECM (Removal).
NEXT -- PERFORM EVAP SYSTEM CHECK (AUTOMATIC MODE)
36. REPAIR OR REPLACE PARTS AND COMPONENTS INDICATED BY OUTPUT DTCS
(a) Repair the malfunctioning areas indicated by the DTCs that had been confirmed when the vehicle was brought in.
NEXT -- PERFORM EVAP SYSTEM CHECK (AUTOMATIC MODE)
37. PERFORM EVAP SYSTEM CHECK (AUTOMATIC MODE)

NOTICE:
- In the Evaporative System Check (Automatic Mode), the series of 5 Evaporative System Check steps is performed automatically. It takes a maximum of approximately 18 minutes.
- Do not perform the Evaporative System Check when the fuel tank is more than 90% full because the cut-off valve may be closed and making the leak check of the fuel tank unavailable.
- Do not run the engine in this step.
- When the temperature of the fuel is 35°C (95°F) or more, a large amount of vapor forms and any check results become inaccurate. When performing an Evaporative System Check, keep the temperature below 35°C (95°F).

(a) Clear DTCs (DTC Check / Clear).
(b) On the Techstream, enter the following menus: Powertrain / Engine and ECT / Utility / Evaporative System Check / Automatic Mode.
(c) After the Evaporative System Check is completed, check for pending DTCs by entering the following menus: Powertrain / Engine and ECT / Trouble Codes / Pending.

HINT: If no pending DTC is found, the repair has been successfully completed.

NEXT -- COMPLETED

MONITOR DESCRIPTION

5 hours* after the ignition switch is turned OFF, the electric leak detection pump creates negative pressure (vacuum) in the EVAP (Evaporative Emission) system. The ECM monitors for leaks and actuator malfunctions based on the EVAP pressure.

HINT: *: If the engine coolant temperature is not below 35°C (95°F) 5 hours after the ignition switch is turned OFF, the monitor check starts 2 hours later. If it is still not below 35°C (95°F) 7 hours after the ignition switch is turned OFF, the monitor check starts 2.5 hours later.

* If only a small amount of fuel is in the fuel tank, it takes longer for the EVAP pressure to stabilize.

1. P2401: Leak detection pump stuck OFF
In operation B, the leak detection pump creates negative pressure (a vacuum) through the reference orifice. The EVAP (Evaporative Emission) system pressure is then measured by the ECM, using the canister pressure sensor, to determine the 0.02 inch leak criterion. If the pressure is higher than -1.06 kPa (-7.95 mmHg)*, or lower than -4.85 kPa (-36.38 mmHg)*, the ECM interprets this as the leak detection pump being stuck OFF (not operating). The ECM illuminates the MIL and sets the DTC (2 trip detection logic).
*: The thresholds vary according to the atmospheric pressure measured in operation A. The values described above are based on an atmospheric pressure of 100 kPa (750.1 mmHg): absolute pressure.

2. P2402: Leak detection pump stuck ON
In operation B, the leak detection pump creates negative pressure (a vacuum) through the reference orifice. The EVAP (Evaporative Emission) system pressure is then measured by the ECM, using the canister pressure sensor, to determine the 0.02 inch leak criterion. If the pressure is higher than -1.06 kPa (-7.95 mmHg)*, or lower than -4.85 kPa (-36.38 mmHg)*, the ECM interprets this as the leak detection pump being stuck ON (remaining ON all the time). The ECM illuminates the MIL and sets the DTC (2 trip detection logic).
*: The thresholds vary according to the atmospheric pressure measured in operation A. The values described above are based on an atmospheric pressure of 100 kPa (750.1 mmHg): absolute pressure.

HINT: The detection logic of DTCs P2401 and P2402 is the same because in both cases the 0.02 inch leak criterion measured in operation B is compared to the atmospheric pressure registered in operation A. The ECM calculates the difference between these pressures by deducting [the 0.02 inch leak criterion] from [the stored atmospheric pressure], and uses this to monitor the EVAP system pressure change.

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

"Saturated" indicates that the EVAP pressure change is less than 0.75 mmHg (0.1 kPa) in 30 seconds.

MONITOR RESULT

Refer to CHECKING MONITOR STATUS (Mode 6 Data).