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Home >> Lexus >> 2008 >> IS 250 RWD V6-2.5L (4GR-FSE) >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> P Code Charts >> P0453

P0453








4GR-FSE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0450: Evaporative Emission Control System Pressure Sensor / Switch

DTC P0450 - Evaporative Emission Control System Pressure Sensor / Switch

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





HINT: The pressure sensor is built into the pump module.

DESCRIPTION









While the engine is running, if a predetermined condition (closed- loop etc.) is met, the EVAP VSV is opened by the ECM and stored fuel vapors in the canister are purged to the intake manifold. The ECM changes the duty cycle ratio of the EVAP VSV to control purge flow volume.
The 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 the purge flow is maintained when the negative pressure (vacuum) is applied to the canister.
The following two monitors run to confirm appropriate EVAP system operation.
1. Key-off monitor
This monitor checks for Evaporative Emission (EVAP) system leaks and pump module malfunctions. The monitor starts 5 hours* after the engine switch is turned off. More than 5 hours are required to allow the fuel to cool down to stabilize the Fuel Tank Pressure (FTP), thus making the EVAP system monitor more accurate.
The electric vacuum pump creates negative pressure (vacuum) in the EVAP system and the pressure is measured. Finally, the ECM monitors for leaks from the EVAP system and malfunctions in both the pump module and EVAP VSV, based on the EVAP pressure.
HINT: *: If the engine coolant temperature is not below 35°C 5 hours after the engine switch is turned off, the monitor check starts 2 hours later. If it is still not below 35°C 7 hours after the engine switch is turned off, the monitor check starts 2.5 hours later.

2. Purge flow monitor
The purge flow monitor consists of the two monitors. The 1st monitor is conducted every time and the 2nd monitor is conducted if necessary.

- The 1st monitor
While the engine is running and the purge Vacuum Switching Valve (VSV) is ON (open), the ECM monitors the purge flow by measuring the EVAP pressure change. If negative pressure is not created, the ECM begins the 2nd monitor.
- The 2nd monitor
The vent valve turned OFF (open) and the EVAP pressure is then measured. If the variation in the pressure is less than 0.5 kPa (3.75 mmHg), the ECM interprets this as the EVAP VSV being stuck closed, and illuminates the MIL and sets DTC P0441 (2 trip detection logic).
- Atmospheric pressure check:
In order to ensure reliable malfunction detection, the variation between the atmospheric pressures, before and after conduction of the purge flow monitor, is measured by the ECM.

















MONITOR DESCRIPTION

1. DTC P0450: Pressure sensor voltage abnormal fluctuation
If the pressure sensor output voltage rapidly fluctuates between less than 0.45 V and more than 4.9 V, the ECM interprets this as an open or short circuit malfunction in the 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: Pressure sensor noising or stuck
If the pressure sensor output voltage fluctuates rapidly for 10 seconds, the ECM stops the EVAP system monitor. The ECM interprets this as noise from the pressure sensor, and stops the EVAP system monitor. The ECM then illuminates the MIL and sets the DTC.
Alternatively, if the sensor output voltage does not change for 10 seconds, the ECM interprets this as the sensor being stuck, and stops the monitor. The ECM then illuminates the MIL and sets the DTC.
(Both the malfunctions are detected by 2 trip detection logic).
3. DTC P0452: Pressure sensor voltage low
If the pressure sensor output voltage is below 0.45 V, the ECM interprets this as an open or short circuit malfunction in the 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: Pressure sensor voltage high
If the pressure sensor voltage output is 4.9 V or more, the ECM interprets this as an open or short circuit malfunction in the 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





TYPICAL ENABLING CONDITIONS

P0450, P0452 and P0453:





P0451 (Noise Monitor):





P0451 (Stuck Monitor):





TYPICAL MALFUNCTION THRESHOLDS

P0450: Canister pressure sensor chattering





P0451: Canister pressure sensor noise





P0451: Canister pressure sensor stuck





P0452: Canister pressure sensor low voltage





P0453: Canister pressure sensor high voltage





WIRING DIAGRAM





INSPECTION PROCEDURE
NOTICE:
- When a vehicle is brought into a workshop, leave it as it is. Do not change the vehicle condition. For example, do not tighten the fuel tank cap.
- Do not disassemble the pump module.
- Techstream is required to conduct the following diagnostic troubleshooting procedure.

PROCEDURE

1. CONFIRM DTC AND EVAP PRESSURE
(a) Connect Techstream to the DLC3.
(b) Turn the engine switch on (do not start the engine).
(c) Turn the tester on.
(d) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
(e) Read DTCs.
(f) Enter the following menus: Powertrain / Engine and ECT / Data List / EVAP / Vapor Pressure Pump.
(g) Read the EVAP (Evaporative Emission) pressure displayed on the tester.
Result:






C -- GO TO EVAP INSPECTION PROCEDURE
B -- CHECK HARNESS AND CONNECTOR (PUMP MODULE - ECM)
A -- Continue to next step.
2. CHECK HARNESS AND CONNECTOR (PUMP MODULE - ECM)





(a) Turn the engine switch off.
(b) Disconnect the A6 ECM connector.
(c) Measure the resistance between the PPMP terminal of the ECM connector and body ground.
Result:





(d) Reconnect the ECM connector.
B -- REPLACE ECM
A -- Continue to next step.
3. CHECK HARNESS AND CONNECTOR (PUMP MODULE - ECM)





(a) Disconnect the Q49 canister pump module pump module connector.
(b) Disconnect the A6 ECM connector.
(c) Measure the resistance between the PPMP terminal of the ECM connector and body ground.
Result:





(d) Reconnect the canister pump module connector.
(e) Reconnect the ECM connector.
B -- REPAIR OR REPLACE HARNESS OR CONNECTOR
A -- REPLACE CHARCOAL CANISTER
4. CHECK HARNESS AND CONNECTOR (PUMP MODULE - ECM)





(a) Disconnect the Q49 canister pump module connector.
(b) Turn the engine switch on (IG).
(c) Measure the voltage and resistance according to the value(s) in the table below.
Standard voltage:






Standard resistance:






Result:





(d) Reconnect the canister pump module connector.
B -- REPAIR OR REPLACE HARNESS OR CONNECTOR
A -- REPLACE CHARCOAL CANISTER
5. REPLACE CHARCOAL CANISTER
NEXT -- CHECK WHETHER DTC OUTPUT (AFTER REPAIR)
6. REPAIR OR REPLACE HARNESS OR CONNECTOR
HINT: If the exhaust tail pipe has been removed, go to the next step before reinstalling it.

NEXT -- CHECK WHETHER DTC OUTPUT (AFTER REPAIR)
7. REPLACE ECM
NEXT -- CHECK WHETHER DTC OUTPUT (AFTER REPAIR)
8. CHECK WHETHER DTC OUTPUT (AFTER REPAIR)
(a) Connect Techstream to the DLC3.
(b) Turn the engine switch on (IG) and turn the tester on.
(c) Wait for at least 60 seconds.
(d) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes / Pending.
HINT: If no pending DTC is displayed on the tester, the repair has been successfully completed.

NEXT -- END
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