- Fuel tank cap (loose)
-
Leak from EVAP line
(Canister - Fuel tank)
-
Leak from EVAP line
(Purge VSV - Canister)
- Canister pump module
- Leak from fuel tank
- Leak from canister
| Last Modified: 11-29-2007 | 1.6 C | |
| Service Category: Engine/Hybrid System | Section: Engine Control | |
| Model Year: 2008 | Model: Sequoia | Doc ID: RM000000SWH03BX |
| Title: 3UR-FE ENGINE CONTROL: SFI SYSTEM: DTC SUMMARY (2008 Sequoia) | ||
|
DTC |
P0455 |
Evaporative Emission Control System Leak Detected (Gross Leak) |
|
DTC |
P0456 |
Evaporative Emission Control System Leak Detected (Very Small Leak) |
DTC SUMMARY
|
DTC No. |
Monitoring Item |
Malfunction Detection Condition |
Trouble Area |
Detection Timing |
Detection Logic |
|---|---|---|---|---|---|
|
P0455 |
EVAP gross leak |
Leak detection pump creates negative pressure (vacuum) in EVAP system and EVAP system pressure measured. Reference pressure measured at start and at end of leak check. If stabilized pressure higher than [second reference pressure x 0.2], ECM determines that EVAP system has large leak. |
|
While ignition switch off |
2 trip |
|
P0456 |
EVAP small leak |
Leak detection pump creates negative pressure (vacuum) in EVAP system and EVAP system pressure measured. Reference pressure measured at start and at end of leak check. If stabilized pressure higher than second reference pressure, ECM determines that EVAP system has small leak. |
|
While ignition switch off |
2 trip |
DESCRIPTION
The description can be found in the EVAP (Evaporative Emission) System
.
INSPECTION PROCEDURE
Refer to the EVAP System
.
MONITOR DESCRIPTION
5 hours* after the ignition switch is turned off, the leak detection pump creates negative pressure (vacuum) in the EVAP 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.
|
Sequence |
Operation |
Description |
Duration |
|---|---|---|---|
|
- |
ECM activation |
Activated by soak timer 5, 7 or 9.5 hours after ignition switch turned off. |
- |
|
A |
Atmospheric pressure measurement |
Vent valve turned OFF (vent) and EVAP system pressure measured by ECM in order to register atmospheric pressure. If pressure in EVAP system not between 70 kPa-a and 110 kPa-a (525 mmHg-a and 825 mmHg-a), ECM cancels EVAP system monitor. |
10 seconds |
|
B |
First reference pressure measurement |
In order to determine reference pressure, leak detection pump creates negative pressure (vacuum) through reference orifice and then ECM checks if leak detection pump and vent valve operate normally. |
60 seconds |
|
C |
EVAP system pressure measurement |
Vent valve turned ON (closed) to shut EVAP system. Negative pressure (vacuum) created in EVAP system, and EVAP system pressure then measured. Write down measured value as it will be used in leak check. If EVAP pressure does not stabilize within 15 minutes, ECM cancels EVAP system monitor. |
15 minutes* |
|
D |
Purge VSV monitor |
Purge VSV opened and then EVAP system pressure measured by ECM. Large increase indicates normality. |
10 seconds |
|
E |
Second reference pressure measurement |
After second reference pressure measurement, leak check performed by comparing first and second reference pressure. If stabilized system pressure higher than second reference pressure, ECM determines that EVAP system leaking. |
60 seconds |
|
- |
Final check |
Atmospheric pressure measured and then monitoring result recorded by ECM. |
- |
*: If only a small amount of fuel is in the fuel tank, it takes longer for the EVAP pressure to stabilize.
(a) P0455: EVAP gross leak
In operation C, the leak detection pump creates negative pressure (vacuum) in the EVAP system and the EVAP system pressure is measured. If the stabilized system pressure is higher than [second reference pressure x 0.2] (near atmospheric pressure), the ECM determines that the EVAP system has a large leak, illuminates the MIL and stores the DTC (2 trip detection logic).
(b) P0456: EVAP very small leak
In operation C, the leak detection pump creates negative pressure (vacuum) in the EVAP system and the EVAP system pressure is measured. If the stabilized system pressure is higher than the second reference pressure, the ECM determines that the EVAP system has a small leak, illuminates the MIL and stores the DTC (2 trip detection logic).
MONITOR STRATEGY
|
Required Sensors/Components |
Purge VSV and canister pump module |
|
Frequency of Operation |
Once per driving cycle |
|
Duration |
Within 15 minutes (varies with amount of fuel in tank) |
|
MIL Operation |
2 driving cycles |
|
Sequence of Operation |
None |
TYPICAL ENABLING CONDITIONS
|
Monitor runs whenever following DTCs not present |
None |
P0455 (Pattern 1), P0456
|
Atmospheric pressure |
70 to 110 kPa-a (525 to 825 mmHg-a) |
|
Battery voltage |
10.5 V or more |
|
Vehicle speed |
Below 4 km/h (2.5 mph) |
|
Ignition switch |
off |
|
Time after key off |
5 or 7 or 9.5 hours |
|
Canister pressure sensor malfunction (P0451, P0452 and P0453) |
Not detected |
|
Purge VSV |
Not operated by scan tool |
|
Vent valve |
Not operated by scan tool |
|
Leak detection pump |
Not operated by scan tool |
|
Both of following conditions met before key off |
Conditions 1 and 2 |
|
1. Duration that vehicle driven |
5 minutes or more |
|
2. EVAP purge operation |
Performed |
|
ECT |
4.4 to 35°C (40 to 95°F) |
|
IAT |
4.4 to 35°C (40 to 95°F) |
P0455 (Pattern 2)
|
Atmospheric pressure |
70 to 110 kPa-a (525 to 825 mmHg-a) |
|
Battery voltage |
10.5 V or more |
|
Vehicle speed |
Below 4 km/h (2.5 mph) |
|
Ignition switch |
off |
|
Canister pressure sensor malfunction (P0451, P0452 and P0453) |
Not detected |
|
Purge VSV |
Not operated by scan tool |
|
Vent valve |
Not operated by scan tool |
|
Leak detection pump |
Not operated by scan tool |
|
Both of the following conditions 1 and 2 set before key off |
- |
|
1. Duration that vehicle has been driven |
5 minutes or more |
|
2. EVAP purge operation |
Performed |
|
ECT |
4.4 to 40°C (40 to 104°F) |
|
IAT |
4.4 to 40°C (40 to 104°F) |
TYPICAL MALFUNCTION THRESHOLDS
P0455 (Pattern 1)
|
EVAP pressure when vacuum introduction complete |
Higher than reference pressure x 0.2 |
P0455 (Pattern 2)
|
EVAP pressure when vacuum introduction complete |
Higher than reference pressure x 0.2 |
P0456
|
EVAP pressure when vacuum introduction complete |
Between reference pressure and reference pressure x 0.2 |
MONITOR RESULT
Refer to Checking Monitor Status
.
|
|