P0451
3MZ-FE 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
The circuit description can be found in the EVAP (Evaporative Emission) Inspection Procedure (Component Tests and General Diagnostics).
MONITOR DESCRIPTION
1 DTC P0450: Pressure sensor abnormal voltage fluctuation
If the 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 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 abnormal voltage fluctuation or being constant
If the pressure sensor voltage output fluctuates rapidly for 10 seconds, the ECM stops the EVAP system monitor. The ECM interprets this as the pressure sensor voltage fluctuating, 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 the malfunctions are detected by 2 trip detection logic.)
3 DTC P0452: Pressure sensor voltage low
If the pressure sensor voltage output 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
All:
P0451 (Noise monitor):
P0451 (Stuck monitor):
P0450, P0452 and P0453:
TYPICAL MALFUNCTION THRESHOLDS
(a) P0450: Pressure sensor chattering
(b) P0451: Pressure sensor noise
(c) P0451: Pressure sensor stuck
(d) P0452: Pressure sensor low voltage
(e) P0453: 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 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 ignition switch to the ON position (do not start the engine).
(c) Turn the tester on.
(d) Select the following menu items: Powertrain / Engine and ECT / Trouble Codes.
(e) Read the DTCs.
(f) Select the following menu items: Powertrain / Engine and ECT / Data List / Vapor Pressure Pump.
(g) Read the EVAP (Evaporative Emission) pressure displayed on the tester.
Result:
C -- GO TO EVAP SYSTEM
B -- CHECK HARNESS AND CONNECTOR (PUMP MODULE - ECM)
A -- Continue to next step.
2. CHECK HARNESS AND CONNECTOR (PUMP MODULE - ECM)
(a) Turn the ignition switch off.
(b) Disconnect the 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 canister pump module connector.
(b) Disconnect the 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 -- REPLACE CHARCOAL CANISTER ASSEMBLY
A -- Continue to next step.
4. REPLACE CHARCOAL CANISTER ASSEMBLY
(a) Replace the charcoal canister assembly (Components).
(b) Connect Techstream to the DLC3.
(c) Turn the ignition switch to the ON position and turn the tester on.
(d) Wait for at least 60 seconds.
(e) Select the following menu items on the tester: Powertrain / Engine and ECT / Trouble Codes.
HINT: If no pending DTC is displayed on the tester, the repair has been successfully completed.
NEXT -- COMPLETED
5. CHECK HARNESS AND CONNECTOR (PUMP MODULE - ECM)
(a) Disconnect the canister pump module connector.
(b) Turn the ignition switch to the ON position.
(c) Measure the voltage and resistance of the canister connector.
Standard:
Result:
(d) Reconnect the canister pump module connector.
B -- REPAIR OR REPLACE WIRE HARNESS OR CONNECTORS
A -- Continue to next step.
6. REPLACE CHARCOAL CANISTER ASSEMBLY
(a) Replace the charcoal canister assembly (Components).
(b) Connect Techstream to the DLC3.
(c) Turn the ignition switch to the ON position and turn the tester on.
(d) Wait for at least 60 seconds.
(e) Select the following menu items on the tester: Powertrain / Engine and ECT / Trouble Codes.
HINT: If no pending DTC is displayed on the tester, the repair has been successfully completed.
NEXT -- COMPLETED
7. REPAIR OR REPLACE WIRE HARNESS OR CONNECTORS
(a) Repair or replace the wire harness or connectors.
(b) Connect Techstream to the DLC3.
(c) Turn the ignition switch to the ON position and turn the tester on.
(d) Wait for at least 60 seconds.
(e) Select the following menu items on the tester: Powertrain / Engine and ECT / Trouble Codes.
HINT: If no pending DTC is displayed on the tester, the repair has been successfully completed.
NEXT -- COMPLETED
8. REPLACE ECM
(a) Replace the ECM (Components).
(b) Connect Techstream to the DLC3.
(c) Turn the ignition switch to the ON position and turn the tester on.
(d) Wait for at least 60 seconds.
(e) Select the following menu items on the tester: Powertrain / Engine and ECT / Trouble Codes.
HINT: If no pending DTC is displayed on the tester, the repair has been successfully completed.
NEXT -- COMPLETED