2UZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0450-P0453; Evaporative Emission Control System Pressure Sensor Malfunction; 2007 MY LX470 [08/2006

Last Modified: 7-3-2017	6.8:8.0.40	Doc ID: RM000000YE600UX
Model Year Start: 2007	Model: LX470	Prod Date Range: [08/2006 - ]
Title: 2UZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0450-P0453; Evaporative Emission Control System Pressure Sensor Malfunction; 2007 MY LX470 [08/2006 - ]

DTC

P0450

Evaporative Emission Control System Pressure Sensor Malfunction

DTC

P0451

Evaporative Emission Control System Pressure Sensor Range / Performance

DTC

P0452

Evaporative Emission Control System Pressure Sensor / Switch Low Input

DTC

P0453

Evaporative Emission Control System Pressure Sensor / Switch High Input

DTC SUMMARY

DTC No.	Monitoring Item	Malfunction Detection Condition	Trouble Area	Detection Timing	Detection logic
P0450	Canister pressure sensor voltage abnormal fluctuation	Sensor output voltage rapidly fluctuates beyond upper and lower malfunction thresholds for 0.5 seconds.	Canister pump module EVAP system hose (pipe from air inlet port to canister pump module, canister filter, fuel tank vent hose) ECM	EVAP monitoring (ignition switch OFF) Ignition switch ON	1 trip
P0451	Canister pressure sensor noisy	Sensor output voltage fluctuates frequently in certain time period.	Canister pump module Connector/wire harness (canister pump module - ECM) EVAP system hose (pipe from air inlet port to canister pump module, canister filter, fuel tank vent hose) ECM	EVAP monitoring (ignition switch OFF) Engine running	2 trip
P0451	Canister pressure sensor stuck	Sensor output voltage does not vary in certain time period.	Canister pump module Connector/wire harness (canister pump module - ECM) EVAP system hose (pipe from air inlet port to canister pump module, canister filter, fuel tank vent hose) ECM	EVAP monitoring (ignition switch OFF)	2 trip
P0452	Canister pressure sensor voltage low	Sensor output voltage less than 0.45 V for 0.5 seconds.	Canister pump module Connector/wire harness (canister pump module - ECM) EVAP system hose (pipe from air inlet port to canister pump module, canister filter, fuel tank vent hose) ECM	EVAP monitoring (ignition switch OFF) Ignition switch ON	1 trip
P0453	Canister pressure sensor voltage high	Sensor output voltage more than 4.9 V for 0.5 seconds.	Canister pump module Connector/wire harness (canister pump module - ECM) EVAP system hose (pipe from air inlet port to canister pump module, canister filter, fuel tank vent hose) ECM	EVAP monitoring (ignition switch OFF) Ignition switch ON	1 trip

HINT:

The Canister pressure sensor is built into the canister pump module.

DESCRIPTION

The circuit description can be found in the Evaporative Emission (EVAP) system .

MONITOR DESCRIPTION

1. DTC P0450: Canister pressure sensor voltage abnormal fluctuation

If the canister pressure sensor voltage output [pressure] rapidly fluctuates between less than 0.45 V [42.1 kPa-a (315.9 mmHg-a)] and more than 4.9 V [123.8 kPa-a (928.4 mmHg-a)], the ECM interprets this as an open or short circuit malfunction in the canister pressure sensor or its circuit, and stops the EVAP (Evaporative Emission) system monitor. The ECM then illuminates the MIL and sets the DTC (1 trip detection logic).

2. DTC P0451: Canister pressure sensor noise or fixed/flat

If the canister pressure sensor voltage output fluctuates rapidly for 10 seconds, the ECM stops the EVAP system monitor. The ECM interprets this as noise from the canister pressure sensor, and stops the EVAP system monitor. The ECM then illuminates the MIL and sets the DTC.

Alternatively, if the sensor voltage output does not change for 10 seconds, the ECM interprets this as the sensor being fixed/flat, and stops the monitor. The ECM then illuminates the MIL and sets the DTC.

(Both of the malfunctions are detected by 2 trip detection logic).

3. DTC P0452: Canister pressure sensor voltage low

If the canister pressure sensor voltage output [pressure] is below 0.45 V [42.1 kPa-a (315.9 mmHg-a)], the ECM interprets this as an open or short circuit malfunction in the canister pressure sensor or its circuit, and stops the EVAP system monitor. The ECM then illuminates the MIL and sets the DTC (1 trip detection logic).

4. DTC P0453: Canister pressure sensor voltage high

If the canister pressure sensor voltage output [pressure] is 4.9 V [123.8 kPa-a (928.4 mmHg-a)] or more, the ECM interprets this as an open or short circuit malfunction in the canister pressure sensor or its circuit, and stops the EVAP system monitor. The ECM then illuminates the MIL and sets the DTC (1 trip detection logic).

MONITOR STRATEGY

Required Sensors/Components	Canister pump module
Frequency of Operation	Once per driving cycle: P0451 sensor fixed/flat Continuous: P0451 sensor noisy, P0450, P0452 and P0453
Duration	0.5 seconds: P0450, P0452 and P0453 Within 2 minutes: P0451
MIL Operation	Immediate: P0450, P0452, P0453 2 driving cycles: P0451
Sequence of Operation	None

TYPICAL ENABLING CONDITIONS

P0451 (Noise Monitor):

Monitor runs whenever following DTCs are not present	None
Atmospheric pressure [absolute pressure]	70 to 110 kPa-a (525 to 825 mmHg-a)
Battery voltage	10.5 V or more
Intake air temperature	4.4 to 35 °C (40 to 95°F)
EVAP canister pressure sensor malfunction (P0450, P0452, P0453)	Not detected
Either of following conditions is met	A or B
A. Engine	Running
B. Soak time (ignition switch OFF time)	5, 7 or 9.5 hours

P0451 (Fixed/flat Monitor):

Monitor runs whenever following DTCs are not present	None
Atmospheric pressure	70 to 110 kPa-a (525 to 825 mmHg-a)
Battery voltage	10.5 V or more
Intake air temperature	4.4 to 35°C (40 to 95°F)
EVAP canister pressure sensor malfunction (P0450, P0452, P0453)	Not detected
Soak time (ignition switch OFF time)	5, 7 or 9.5 hours

P0450, P0452 and P0453:

Monitor runs whenever following DTCs are not present	None
Either of following conditions is met	A or B
A. Ignition switch	ON
B. Soak time	ON

TYPICAL MALFUNCTION THRESHOLDS

P0450: Canister pressure sensor chattering

EVAP pressure

Less than 42.1 kPa-a (315.9 mmHg-a), or more than 123.8 kPa-a (928.4 mmHg-a)

P0451: Canister pressure sensor noise

Pressure variation indicated by canister pressure sensor in 10 seconds

More than 0.3 kPa-g (2.25 mmHg-g) 10 times

P0451: Canister pressure sensor fixed/flat

EVAP pressure change during reference pressure measurement

Less than 0.65 kPa-g (4.87 mmHg-g)

P0452: Canister pressure sensor low voltage

EVAP pressure

Less than 42.1 kPa-a (315.9 mmHg-a)

P0453: Canister pressure sensor high voltage

EVAP pressure

More than 123.8 kPa-a (928.4 mmHg-a)

WIRING DIAGRAM

INSPECTION PROCEDURE

NOTICE:

When a vehicle is brought into the workshop, leave it as it is. Do not change the vehicle condition. For example, do not tighten the fuel cap.

Do not disassemble the canister pump module.

The intelligent tester is required to conduct the following diagnostic troubleshooting procedure.

PROCEDURE

1.	CONFIRM DTC AND EVAP PRESSURE

(a) Connect the intelligent tester to the CAN VIM. Then connect the CAN VIM to the DLC3.

(b) Turn the ignition switch ON and turn the intelligent tester ON.

(d) Read the values.

(e) Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / EVAP / VAPOR PRESS.

(f) Read the EVAP pressure displayed on the intelligent tester.

Display (DTC Output)	Test Result	Suspected Trouble Area	Proceed to
P0451	-	Canister pressure sensor	A
P0452	Less than 45 kPa-a (430 mmHg-a)	Wire harness/connector (ECM - Canister pressure sensor) Canister pressure sensor Short in ECM circuit	B
P0453	More than 120 kPa-a (900 mmHg-a)	Wire harness/connector (ECM - Canister pressure sensor) Canister pressure sensor Open in ECM circuit	C

GO TO EVAP SYSTEM

GO TO STEP 4

2.	CHECK HARNESS AND CONNECTOR (CANISTER PUMP MODULE - ECM)

(a) Disconnect the E10 ECM connector.

(b) Turn the ignition switch OFF.

Test Result	Suspected Trouble Area	Proceed to
10 Ω or less	Wire harness/connector (ECM - Canister pressure sensor) Short in canister pressure sensor circuit	A
10 kΩ or more	Wire harness/connector (ECM - Canister pressure sensor) Short in ECM circuit	B

GO TO STEP 7

3.	CHECK HARNESS AND CONNECTOR (CANISTER PUMP MODULE - ECM)

(a) Disconnect the L4 canister pump module connector.

(b) Disconnect the E10 ECM connector.

Test Result	Suspected Trouble Area	Proceed to
10 kΩ or more	Short in canister pressure sensor circuit	A
10 Ω or less	Short in wire harness/connector (ECM - Canister pressure sensor)	B

GO TO STEP 5

GO TO STEP 6

4.	CHECK HARNESS AND CONNECTOR (CANISTER PUMP MODULE - ECM)

(a) Disconnect the L4 canister pump module connector.

(b) Turn the ignition switch ON.

Standard:

Tester Connection	Specified Condition
VCC (L4-4) - Body ground	4.5 to 5.0 V
VOUT (L4-3) - Body ground	4.5 to 5.0 V
SGND (L4-2) - Body ground	100 Ω or less

Test Result	Suspected Trouble Area	Proceed to
Voltage and resistance within standard ranges	Open in canister pressure sensor circuit	A
Voltage and resistance outside standard ranges	Open in wire harness/connector (ECM - canister pressure sensor)	B

GO TO STEP 5

GO TO STEP 6

5.	REPLACE CANISTER ASSEMBLY

(a) Replace the canister assembly .

NOTICE:

When replacing the canister, check the canister pump module interior and related pipes for water, fuel and 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.

GO TO STEP 8

6.	REPAIR OR REPLACE HARNESS OR CONNECTOR

HINT:

If the exhaust tailpipe has been removed, go to the next step before reinstalling it.

GO TO STEP 8

7.	REPLACE ECM

(a) Replace the ECM .

GO TO STEP 8

8.	CHECK WHETHER DTC OUTPUT RECURS (AFTER REPAIR)

(a) Connect the intelligent tester to the CAN VIM. Then connect the CAN VIM to the DLC3.

(b) Turn the ignition switch ON and turn the intelligent tester ON.

(d) Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DTC INFO / PENDING CODES.

HINT:

If no pending DTC is displayed on the intelligent tester, the repair has been successfully completed.

COMPLETED