P0452
1NZ-FXE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0450: Evaporative Emission Control System Pressure Sensor Malfunction
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
HINT: The canister pressure sensor is built into the canister pump module.
DESCRIPTION
NOTE: In this vehicle's EVAP system, turning ON the vent valve does not seal off the EVAP system. To check for leaks in the EVAP system, disconnect the air inlet vent hose and apply pressure from the atmosphere side of the canister.
While the engine is running, if a predetermined condition (closed loop, etc.) is met, the purge VSV is opened by the ECM and the stored fuel vapors in the canister are purged to the intake manifold. The ECM changes the duty cycle ratio of the purge 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.
Key-off monitor
This monitor checks for Evaporative Emission (EVAP) system leaks and canister pump module malfunctions. The monitor starts 5 hours* after the power 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 leak detection 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 canister pump module and purge VSV, based on the EVAP pressure.
HINT: *: If the engine coolant temperature is not below 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 below 35°C (95°F) 7 hours after the power switch is turned OFF, the monitor check starts 2.5 hours later.
MONITOR DESCRIPTION
1. DTC P0450: Canister pressure sensor voltage abnormal fluctuation
If the canister pressure sensor voltage output 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 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).
2. DTC P0451: Canister pressure sensor noisy or stuck
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 stuck, 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 is below 0.45 V, 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 is 4.9 V 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
TYPICAL ENABLING CONDITIONS
P0451 (Noise Monitor):
P0451 (Stuck Monitor):
P0450, P0452 and P0453:
TYPICAL MALFUNCTION THRESHOLDS
1. P0450: Canister pressure sensor chattering
2 P0451: Canister pressure sensor noise
3 P0451: Canister pressure sensor stuck
4 P0452: Canister pressure sensor low voltage
5 P0453: Canister pressure sensor high voltage
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.
- 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 power switch ON (IG) and turn Techstream ON.
(c) Enter the following menus: Powertrain / Engine and ECT / Trouble Code.
(d) Read the values.
(e) Enter the following menus: Powertrain / Engine and ECT / Data List / Evap Vapor Press.
(f) Read the EVAP pressure displayed on Techstream.
Result:
C -- CHECK HARNESS AND CONNECTOR (CANISTER PUMP MODULE - ECM)
A -- REPLACE CANISTER ASSEMBLY
B -- Continue to next step.
2. CHECK HARNESS AND CONNECTOR (CANISTER PUMP MODULE - ECM)
(a) Turn the power switch OFF.
(b) Disconnect the E7 ECM connector.
(c) Measure the resistance between the PPMP (E7-30) terminal of the ECM connector and body ground.
Result:
B -- REPLACE ECM
A -- Continue to next step.
3. CHECK HARNESS AND CONNECTOR (CANISTER PUMP MODULE - ECM)
(a) Disconnect the V7 canister pump module connector.
(b) Disconnect the E7 ECM connector.
(c) Measure the resistance between the PPMP (E7-30) terminal of the ECM connector and body ground.
Result:
B -- REPAIR OR REPLACE HARNESS OR CONNECTOR
A -- Continue to next step.
4. CHECK HARNESS AND CONNECTOR (CANISTER PUMP MODULE - ECM)
(a) Disconnect the V7 canister pump module connector.
(b) Turn the power switch ON (IG).
(c) Measure the voltage and resistance according to the value(s) in the table below.
Standard voltage:
Standard resistance:
Result:
B -- REPAIR OR REPLACE HARNESS OR CONNECTOR
A -- Continue to next step.
5. REPLACE CANISTER ASSEMBLY
(a) Replace the canister assembly (Removal).
NOTE: When replacing the canister, check the canister pump module interior and related pipes for water, fuel or 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.
NEXT -- CHECK WHETHER DTC OUTPUT RECURS (AFTER REPAIR)
6. REPAIR OR REPLACE HARNESS OR CONNECTOR
HINT: If the exhaust tailpipe has been removed, go to the next step before reinstalling it.
NEXT -- CHECK WHETHER DTC OUTPUT RECURS (AFTER REPAIR)
7. REPLACE ECM
(a) Replace the ECM (Removal).
NEXT -- CHECK WHETHER DTC OUTPUT RECURS (AFTER REPAIR)
8. CHECK WHETHER DTC OUTPUT RECURS (AFTER REPAIR)
(a) Connect Techstream to the DLC3.
(b) Turn the power switch ON (IG) and turn Techstream ON.
(c) Wait for at least 60 seconds.
(d) Enter the following menus: Powertrain / Engine and ECT / Trouble Code / Pending.
HINT: If no pending DTC is displayed on Techstream, the repair has been successfully completed.
NEXT -- COMPLETED