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P0451





2AZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0451-P0453: Evaporative Emission Control System Pressure Sensor Range / Performance

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 canister pressure sensor is built into the canister pump module.

DESCRIPTION

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

MONITOR DESCRIPTION





1. 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 stores 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 stores the DTC.

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

2. DTC P0452: Canister pressure sensor voltage low

If the canister pressure sensor voltage output [pressure] is below 0.45 V (42.1 kPa(abs) [315.7 mmHg(abs)]), 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 stores the DTC (1 trip detection logic).

3. DTC P0453: Canister pressure sensor voltage high

If the canister pressure sensor voltage output [pressure] is 4.9 V (123.8 kPa(abs) [928.5 mmHg(abs)]) 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 stores the DTC (1 trip detection logic).

MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS

P0451 (Noise monitor):





P0451 (Fixed/flat monitor):





P0452 and P0453:





TYPICAL MALFUNCTION THRESHOLDS

P0451: Canister pressure sensor noise





P0451: Canister pressure sensor fixed/flat





P0452: Canister pressure sensor low voltage





P0453: Canister pressure sensor high voltage





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 19 minutes.
- Do not perform the Evaporative System Check when the fuel tank is more than 90% 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 below 35°C (95°F).

1. Connect the Techstream to the DLC3.

2. Turn the ignition switch to ON and turn the Techstream on.

3. Enter the following menus: Powertrain / Engine and ECT / Data List / Intake Air.

4. Clear DTCs (even if no DTCs are stored, perform the clear DTC operation).

5. Turn the ignition switch off and wait for at least 30 seconds.

6. Turn the ignition switch to ON and turn the Techstream on.

7. Enter the following menus: Powertrain / Engine and ECT / Utility / Evaporative System Check / Automatic Mode.

8. After the "Evaporative System Check" is completed, check All Readiness by entering the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

9. Input the DTC: P0451, P0452 or P0453.

10. Check the DTC judgment result.





HINT
If the judgment result shows ABNORMAL, the system has a malfunction.

11. If the result is INCOMPLETE or UNKNOWN and no pending DTC is output, perform a universal trip and check for permanent DTCs Reading and Clearing Diagnostic Trouble Codes.

HINT
- If a permanent DTC is output, the system is malfunctioning.
- If no permanent DTC is output, the system is normal.

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 Techstream is required to conduct the following diagnostic troubleshooting procedure.

PROCEDURE

1. CONFIRM DTC AND EVAP PRESSURE

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON (do not start the engine).

(c) Turn the Techstream 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 / Vapor Pressure Pump.

(g) Read the EVAP (Evaporative Emission) pressure displayed on the Techstream.

Result





B -- CHECK HARNESS AND CONNECTOR (CANISTER - ECM)

C -- GO TO EVAP SYSTEM EVAP System
A -- Continue to next step.

2. CHECK HARNESS AND CONNECTOR (CANISTER - ECM)





(a) Turn the ignition switch off.

(b) Disconnect the ECM connector.

(c) Measure the resistance according to the value(s) in the table below.

Result





(d) Reconnect the ECM connector.

B -- REPLACE ECM
A -- Continue to next step.

3. CHECK HARNESS AND CONNECTOR (CANISTER - ECM)





(a) Disconnect the canister pump module connector.

(b) Disconnect the ECM connector.

(c) Measure the resistance according to the value(s) in the table below.

Result





(d) Reconnect the canister pump module connector.

(e) Reconnect the ECM connector.

A -- REPLACE CANISTER

B -- REPAIR OR REPLACE HARNESS OR CONNECTOR (CANISTER - ECM)

4. CHECK HARNESS AND CONNECTOR (CANISTER - ECM)





(a) Disconnect the canister pump module connector.

(b) Measure the voltage and resistance according to the value(s) in the table below.

Standard Voltage:





Standard Resistance:





Result





(c) Reconnect the canister pump module connector.

B -- REPAIR OR REPLACE HARNESS OR CONNECTOR (CANISTER - ECM)
A -- Continue to next step.

5. REPLACE CANISTER

(a) Replace the canister Removal.

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.





NEXT -- CHECK WHETHER DTC OUTPUT RECURS (AFTER REPAIR)

6. REPAIR OR REPLACE HARNESS OR CONNECTOR (CANISTER - ECM)

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 the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Wait for at least 60 seconds.

(e) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes / Pending.

HINT
If no pending DTCs are displayed on the Techstream, the repair has been successfully completed.

NEXT -- END
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