Lexus NX: Evaporative Emission System Leak Detection Reference Orifice Low Flow (P043E,P043F,P2401,P2402,P2419)

Lexus NX Service Manual / Engine & Hybrid System / 2ar-fxe (engine Control) / Sfi System / Evaporative Emission System Leak Detection Reference Orifice Low Flow (P043E,P043F,P2401,P2402,P2419)

DTC SUMMARY

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	MIL	Memory
P043E	Evaporative Emission System Leak Detection Reference Orifice Low Flow	Reference orifice clogged during key-off EVAP monitor	Canister pump module Connector/wire harness (Canister pump module - ECM) ECM	Comes on	DTC stored
P043F	Evaporative Emission System Leak Detection Reference Orifice High Flow	Reference orifice high-flow during key-off EVAP monitor	Canister pump module Connector/wire harness (Canister pump module - ECM) ECM	Comes on	DTC stored
P2401	Evaporative Emission Leak Detection Pump Stuck OFF	Leak detection pump off malfunction during key-off EVAP monitor	Canister pump module Connector/wire harness (Canister pump module - ECM) ECM	Comes on	DTC stored
P2402	Evaporative Emission Leak Detection Pump Stuck ON	Leak detection pump on malfunction during key-off EVAP monitor	Canister pump module Connector/wire harness (Canister pump module - ECM) ECM	Comes on	DTC stored
P2419	Evaporative Emission Pressure Switching Valve Stuck ON	Vent valve on (closed) malfunction during key-off EVAP monitor	Canister pump module Connector/wire harness (Canister pump module - ECM) ECM	Comes on	DTC stored

DTC No.	Monitoring Item	Detection Timing	Detection Logic
P043E	Reference orifice clogged	While power switch off	2 trip
P043F	Reference orifice high-flow
P2401	Leak detection pump stuck off
P2402	Leak detection pump stuck on
P2419	Vent valve stuck closed

HINT:

The reference orifice is located inside the canister pump module.

DESCRIPTION

The description can be found in EVAP (Evaporative Emission) System.

Click here

MONITOR DESCRIPTION

5 hours* after the power 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 less than 35°C (95°F) 5 hours after the power switch is turned off, the monitor check starts 2 hours later. If it is still not less than 35°C (95°F) 7 hours after the power 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 power switch turned off.	-
A	Atmospheric pressure measurement	Vent valve is turned off (vent) and EVAP system pressure is measured by ECM in order to register atmospheric pressure. If pressure in EVAP system is not between 70 kPa(abs) and 111 kPa(abs) [525 mmHg(abs) and 836 mmHg(abs)], ECM cancels EVAP system monitor.	60 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.	360 seconds
C	EVAP system pressure measurement	Vent valve is turned on (closed) to shut EVAP system. Negative pressure (vacuum) is created in EVAP system, and EVAP system pressure is 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 is opened and then EVAP system pressure is measured by ECM. Large increase indicates normal.	10 seconds
E	Second reference pressure measurement	After second reference pressure measurement, leak check is performed by comparing first and second reference pressure measurements. If stabilized system pressure is higher than second reference pressure, ECM determines that EVAP system is leaking.	60 seconds
-	Final check	Atmospheric pressure is measured and then monitoring result is recorded by ECM.	-

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

*1	Purge VSV: Off (Closed)	*2	Purge VSV: On (Open)
*3	Vent Valve: Off (Vent)	*4	Vent Valve: On (Closed)
*5	Leak Detection Pump: Off	*6	Leak Detection Pump: On
*7	Reference Orifice (0.02 inch)	*8	Canister Pressure Sensor
*9	Canister	*10	Fuel Tank
*11	Canister Pump Module	*12	Canister Filter
*a	Operation A: Atmospheric Pressure Measurement	*b	Operation B, E: Reference Pressure Measurement
*c	Operation C: EVAP System Pressure Measurement	*d	Operation D: Purge VSV Monitor
*e	Atmospheric Pressure	*f	Negative Pressure

The leak detection pump creates negative pressure through the reference orifice (in operation B and E). When the system is normal, the EVAP pressure is between 97 to 100 kPa(abs) [726 to 750 mmHg(abs)]* and saturated within a minute. If not, the ECM interprets this as a malfunction. The ECM illuminates the MIL and stores a DTC if this malfunction is detected in consecutive drive cycles.

*: Typical value.

MONITOR STRATEGY

Required Sensors/Components (Main)	Canister pump module
Required Sensors/Components (Related)	-
Frequency of Operation	Once per driving cycle
Duration	Within 7 minutes
MIL Operation	2 driving cycles
Sequence of Operation	None

TYPICAL ENABLING CONDITIONS

Monitor runs whenever the following DTCs are not stored	None
Atmospheric pressure	70 kPa(abs) [525 mmHg(abs)] or higher, and less than 111 kPa(abs) [836 mmHg(abs)]
Auxiliary battery voltage	10.5 V or higher
Vehicle speed	Less than 4 km/h (2.5 mph)
Power switch	Off
Time after key-off	5, 7 or 9.5 hours
Canister pressure sensor malfunction (P0452, 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 met before key-off	Conditions 1 and 2
1. Duration that vehicle is driven	5 minutes or more
2. EVAP purge operation	Performed
Engine coolant temperature	4.4°C (40°F) or higher, and less than 35°C (95°F)
Intake air temperature	4.4°C (40°F) or higher, and less than 35°C (95°F)

TYPICAL MALFUNCTION THRESHOLDS

"Saturated" indicates that the EVAP pressure change is less than 0.286 kPa(gauge) [2.145 mmHg(gauge)] in 60 seconds.

One of following conditions met	-
EVAP pressure just after reference pressure measurement started	Higher than -0.25 kPa(gauge) [-1.875 mmHg(gauge)]
Reference pressure	Less than -4.85 kPa(gauge) [-36.38 mmHg(gauge)]
Reference pressure	-1.057 kPa(gauge) [-7.929 mmHg(gauge)] or higher
Reference pressure	Not saturated within 360 seconds
Difference between first reference pressure and second reference pressure	0.9 kPa(gauge) [6.75 mmHg(gauge)] or higher

MONITOR RESULT

Refer to EVAP System.

Click here

CONFIRMATION DRIVING PATTERN

NOTICE:

The Evaporative System Check (Automatic Mode) consists of 6 steps performed automatically by the Techstream. It takes a maximum of approximately 24 minutes.
Do not perform the Evaporative System Check when the fuel tank is more than 85% full because the cut-off valve may be closed, making the fuel tank leak check unavailable.
Do not run the engine during this operation.
When the temperature of the fuel is 35°C (95°F) or higher, a large amount of vapor forms and any check results become inaccurate. When performing the Evaporative System Check, keep the fuel temperature less than 35°C (95°F).

Connect the Techstream to the DLC3.
Turn the power switch on (IG) and turn the Techstream on.
Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
Turn the power switch off and wait for at least 30 seconds.
Turn the power switch on (IG) and turn the Techstream on.
Enter the following menus: Powertrain / Engine and ECT / Utility / Evaporative System Check / Automatic Mode.
After the "Evaporative System Check" is completed, check for All Readiness by entering the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
Input the DTC: P043E, P043F, P2401, P2402 or P2419.

Check the DTC judgment result.

Techstream Display	Description
NORMAL	DTC judgment completed System normal
ABNORMAL	DTC judgment completed System abnormal
INCOMPLETE	DTC judgment not completed Perform driving pattern after confirming DTC enabling conditions
N/A	Unable to perform DTC judgment Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit

HINT:

If the judgment result shows NORMAL, the system is normal.
If the judgment result shows ABNORMAL, the system has a malfunction.

If the judgment result is INCOMPLETE or N/A and no pending DTC is output, perform a universal trip and check for permanent DTCs.
Click here
HINT:
- If a permanent DTC is output, the system is malfunctioning.
- If no permanent DTC is output, the system is normal.

PROCEDURE

1.	GO TO EVAP SYSTEM

(a) Refer to EVAP System.

Click here

END

SEE MORE:

Components

COMPONENTS ILLUSTRATION *1 SIDE MUDGUARD SUB-ASSEMBLY LH *2 GROMMET ● Non-reusable part - - ILLUSTRATION *1 NO. 3 MOULDING TAPE - - ● Non-reusable part - -

Problem Symptoms Table

PROBLEM SYMPTOMS TABLE HINT: Use the table below to help determine the cause of problem symptoms. If multiple suspected areas are listed, the potential causes of the symptoms are listed in order of probability in the "Suspected Area" column of the table. Check each symptom by checking the suspect

Lexus NX: Evaporative Emission System Leak Detection Reference Orifice Low Flow (P043E,P043F,P2401,P2402,P2419)

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Problem Symptoms Table