Part 1
2AZ-FXE ENGINE CONTROL SYSTEM: SFI SYSTEM: P1422,P1423: Fuel Tank Small Leak
DTC P1422 - Fuel Tank Small Leak
DTC P1423 - Fuel Tank Gross Leak
DTC SUMMARY
DESCRIPTION
While the engine is running, if a predetermined condition (closed loop, etc.) is met, the purge VSV is opened by the ECM (included in hybrid vehicle control ECU) and stored fuel vapors in the canister are purged to the intake manifold. The ECM will change the duty cycle ratio of the purge VSV to control purge flow volume.
Purge flow volume is also determined by the intake manifold pressure. Atmospheric pressure is allowed into the canister through the vent valve to ensure that purge flow is maintained when negative pressure (vacuum) is applied to the canister.
The ECM monitors the condition of both the key-off monitor and purge flow monitor to ensure proper operation of the EVAP system.
Key-off monitor
This monitoring system checks for canister pump module malfunctions and leaks from the EVAP and closed tank systems. Be sure to leave the vehicle for at least 5 hours to sufficiently cool the fuel and stabilize fuel tank pressure. This makes EVAP system monitoring more accurate.
HINT: If the engine coolant temperature is 35°C (95°F) or more, 5 hours after the power switch has been turned off, the ECM will begin performing a monitor check after another 2 hours. If the engine coolant temperature is still 35°C (95°F) or more, 7 hours after the power switch has been turned off, the ECM will begin performing a monitor check after another 2.5 hours.
There are two methods for monitoring the EVAP system.
1. If the fuel tank pressure is higher or lower than the atmospheric pressure, the system determines that there are no leaks in the closed tank system and the system will check for leaks from the piping and canister between the purge VSV and canister pump module. (Method A)
2. If the fuel tank pressure is almost the same as the atmospheric pressure, vacuum pressure will enter the fuel tank and the system will check for leaks from the fuel tank after checking for leaks from the canister. (Method B)
HINT: *: If there is only a small amount of fuel in the fuel tank, stabilizing the EVAP pressure takes longer than usual.
Purge flow monitor
If EVAP system pressure change is less than 7.5 mmHg (1 kPa) when the engine is running and the purge VSV is turned ON (closed), the ECM determines that the purge flow is insufficient.
RELATED DTCS
MONITOR DESCRIPTION
1. P1422: Fuel tank very small leak
In operation G, the vacuum pump creates negative pressure (vacuum) in the fuel tank and the fuel tank pressure is measured. If the stabilized system pressure is higher than the third 0.02 inch leak pressure standard, the ECM (included in the hybrid vehicle control ECU) determines that the fuel tank has a large leakage. The ECM illuminates the MIL and sets the DTC (2-trip detection logic).
2. P1423: Fuel tank gross leak
In operation G, the vacuum pump creates negative pressure (vacuum) in the fuel tank and the fuel tank pressure is measured. If the stabilized system pressure is higher than [third 0.02 inch leak pressure standard x 0.2] (near atmospheric pressure), the ECM (included in the hybrid vehicle control ECU) determines that the fuel tank has a large leakage. The ECM illuminates the MIL and sets the DTC (2-trip detection logic).
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
Example of restart time:
Key-off monitor sequence 1 to 15
1. Atmospheric pressure measurement
2. First reference pressure measurement
3. Vent valve stuck closed check
4. Vacuum introduction for canister
5. Purge VSV stuck closed check
6. Second reference pressure measurement
7. Canister leak
8. Fuel vapor-containment valve (FVCV stuck closed check)
9. Vacuum introduction for fuel tank
10. FVCV stuck closed check
11. FTP sensor stuck check
12. Third reference pressure measurement
13. Fuel tank leak check
14. FTP sensor stuck check
15. Atmospheric pressure measurement
TYPICAL MALFUNCTION THRESHOLDS
"Saturated" indicates that the fuel tank pressure change is less than 0.1 kPa (0.75 mmHg) in 30 seconds.
P1423: Fuel tank gross leak
P1422: Fuel tank small leak
MONITOR RESULT
Refer to CHECKING MONITOR STATUS Engine Control System - SFI System.
INSPECTION PROCEDURE
PROCEDURE
1. CONFIRM DTC
(a) Turn the power switch off and wait 10 seconds.
(b) Turn the power switch on (IG).
(c) Turn the power switch off and wait 10 seconds.
(d) Connect the intelligent tester to the DLC3.
(e) Turn the power switch on (IG) and turn the tester on.
(f) Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
(g) Confirm the DTCs.
DTC and Malfunction Cross-Reference:
NEXT -- Continue to next step.
2. PERFORM SYSTEM CHECK (EVAP SYSTEM CHECK (AUTOMATIC OPERATION))
NOTICE:
- In EVAP SYSTEM CHECK (AUTOMATIC OPERATION), a series of 6 EVAP SYSTEM CHECK steps are performed automatically. A maximum of 15 minutes is required.
- Do not perform EVAP SYSTEM CHECK when the fuel tank is more than 90% full because the cut-off valve may be closed and the leak check of the fuel tank is unavailable.
- Do not run the engine.
- 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 EVAP SYSTEM CHECK, keep the temperature below 35°C (95°F).
(a) Clear the DTCs with the intelligent tester.
(b) Remove the fuel tank cap and reinstall the fuel cap.
(c) Enter the following menus: DIAGNOSIS / ENHANCED OBD II / SYSTEM CHECK / EVAP SYS CHECK / AUTO OPERATION.
(d) After EVAP SYSTEM CHECK is completed, check for DTCs.
Result:
C -- END
B -- PERFORM SYSTEM CHECK (EVAP SYSTEM CHECK (MANUAL OPERATION))
A -- Continue to next step.
3. IDENTIFICATION OF TROUBLE AREAS
(a) Identification of trouble areas according to DTCs.
(b) Refer to the table below to determine the next procedure according to the output DTCs.
Result:
B -- PERFORM ACTIVE TEST USING INTELLIGENT TESTER (VACUUM PUMP)
A -- Continue to next step.
4. IDENTIFICATION OF TROUBLE AREAS
(a) Identification of trouble areas according to DTCs.
(b) Refer to the table below to determine the next procedure according to the output DTCs.
Result:
D -- CHECK FUEL VAPOR-CONTAINMENT VALVE ASSEMBLY (POWER SOURCE CIRCUIT)
C -- LOCATE EVAP LEAK PART (FUEL VAPOR-CONTAINMENT VALVE - FUEL TANK)
B -- LOCATE EVAP LEAK PART (PURGE VSV - CANISTER)
A -- Continue to next step.
5. CHECK VACUUM HOSE (PURGE VSV - INTAKE MANIFOLD)
(a) Disconnect the hose (to intake manifold) from the purge VSV.
(b) Put the engine in inspection mode Component Tests and General Diagnostics.
(c) Use your finger and confirm that the purge VSV has suction.
Result:
NG -- REPAIR OR REPLACE VACUUM HOSE
OK -- Continue to next step.
6. PERFORM ACTIVE TEST USING INTELLIGENT TESTER (PURGE VSV)
(a) Disconnect the hose (to canister) from the purge VSV.
(b) Put the engine in inspection mode Component Tests and General Diagnostics.
(c) Enter the following menu: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / EVAP VSV (ALONE).
(d) Turn the purge VSV OFF (Purge VSV: OFF).
(e) Use your finger and confirm that the purge VSV has no suction.
(f) Turn the purge VSV ON (Purge VSV: ON).
(g) Use your finger to confirm that the purge VSV has suction.
OK:
Purge VSV functions normally
OK -- REPAIR OR REPLACE VACUUM HOSE
NG -- Continue to next step.
7. CHECK PURGE VSV
(a) Remove the purge VSV.
(b) Apply compressed air to the purge VSV, confirm that no air flows from A to B as shown in the illustration.
(c) Apply battery voltage to the purge VSV.
(d) While applying compressed air, confirm that air flows from A to B as shown in the illustration.
Result:
NG -- REPLACE PURGE VSV
OK -- Continue to next step.
8. CHECK HARNESS AND CONNECTOR (PURGE VSV - EFI NO.2 FUSE)
(a) Disconnect the C6 purge VSV connector.
(b) Turn the power switch on (IG).
(c) Measure the voltage between terminal 1 of the E18 connector and body ground.
Result:
NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- Continue to next step.
9. CHECK HARNESS AND CONNECTOR (PURGE VSV - HV CONTROL ECU)
(a) Disconnect the C64 hybrid vehicle control ECU connector and the C6 purge VSV connector.
(b) Measure the resistance.
Standard resistance:
NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- Continue to next step.
10. REPLACE HYBRID VEHICLE CONTROL ECU
NEXT -- PERFORM SYSTEM CHECK (EVAP SYSTEM CHECK AGAIN (AUTOMATIC OPERATION))
11. PERFORM ACTIVE TEST USING INTELLIGENT TESTER (VACUUM PUMP)
(a) Connect the intelligent tester to the DLC3.
(b) Turn the power switch on (IG).
(c) Enter the following menus: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / VACUUM PUMP.
(d) Turn the leak detection pump ON with the tester.
(e) Touch the canister pump module and check if the pump is moving.
OK:
Pump operates
NG -- PERFORM ACTIVE TEST USING INTELLIGENT TESTER (VACUUM PUMP)
OK -- Continue to next step.
12. PERFORM ACTIVE TEST USING INTELLIGENT TESTER (VENT VALVE)
(a) Remove the canister lower cover.
(b) Connect the intelligent tester to the DLC3.
(c) Turn the power switch on (IG).
(d) Enter the following menus: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / VENT VALVE.
(e) Touch the canister pump module, use the tester to turn the vent valve ON and OFF, and check if the vent valve is moving.
OK:
Vent valve vibration can be felt.
NG -- INSPECT CANISTER PUMP MODULE (VENT VALVE OPERATION)
OK -- REPLACE CANISTER ASSEMBLY
13. PERFORM ACTIVE TEST USING INTELLIGENT TESTER (VACUUM PUMP)
(a) Turn the power switch off.
(b) Remove the canister lower cover.
(c) Disconnect the canister pump module connector.
(d) Connect the intelligent tester to the DLC3.
(e) Turn the power switch on (IG).
(f) Enter the following menus: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / VACUUM PUMP.
(g) Turn the leak detection pump ON with the tester.
(h) Measure the voltage between MTRB terminal 1 of the canister pump module connector and body ground when the leak detection pump is turned ON and OFF using the tester.
Standard voltage:
10 to 14 V
NG -- CHECK HARNESS AND CONNECTOR (ECM - CANISTER PUMP MODULE)
OK -- Continue to next step.
14. CHECK HARNESS AND CONNECTOR (CANISTER PUMP MODULE - BODY GROUND)
(a) Remove the canister lower cover.
(b) Disconnect the canister pump module connector.
(c) Measure the resistance between the MGND terminal of the canister pump module and body ground.
Standard resistance:
Below 1 Ohms
NG -- REPAIR OR REPLACE VACUUM HOSE
OK -- REPLACE CANISTER ASSEMBLY
15. CHECK HARNESS AND CONNECTOR (ECM - CANISTER PUMP MODULE)
(a) Disconnect the A61 ECM connector.
(b) Disconnect the canister pump module connector.
(c) Measure the resistance between the MPMP terminal of the Hybrid control ECU connector and the MTRB terminal of the canister pump module connector.
Standard resistance:
NG -- REPAIR OR REPLACE VACUUM HOSE
OK -- REPLACE HYBRID VEHICLE CONTROL ECU
16. INSPECT CANISTER PUMP MODULE (VENT VALVE OPERATION)
(a) Turn the power switch off.
(b) Remove the canister lower cover.
(c) Disconnect the canister pump module connector.
(d) Apply battery voltage to the VLVB and VGND terminals of the canister pump module.
(e) Touch the canister pump module to confirm the vent valve operation.
Result:
(f) Reconnect the canister connector.
B -- REPLACE CANISTER ASSEMBLY
A -- Continue to next step.