DTC P0451:00 [SKYACTIV-G 2.5]

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2014 - Mazda6 - Engine

DTC P0451:00 [SKYACTIV-G 2.5]

NOTE:

To determine the malfunctioning part, proceed with the diagnostics from "Function Inspection Using M-MDS".

Details On DTCs


DESCRIPTION	Fuel tank pressure sensor: sensor characteristic malfunction
DETECTION CONDITION	Determination conditions	The fuel tank pressure sensor input voltage is the threshold or more.
	Preconditions	Battery voltage: above 8 V^1 Period ignition is switched off before engine starts: 120 min or more* Purge solenoid valve not operating The following DTCs are not detected: Purge solenoid valve: P0443:00 Evaporative passage blockage: P1450:00 ^*1: Value can be verified by displaying PIDs using M-MDS
	Malfunction determination period	During one drive cycle
	Drive cycle	1
	Self test type	CMDTC self test
	Sensor used	Fuel tank pressure sensor
FAIL-SAFE FUNCTION	Not applicable
VEHICLE STATUS WHEN DTCs ARE OUTPUT	Illuminates check engine light.
POSSIBLE CAUSE	Fuel tank pressure sensor connector or terminals malfunction PCM connector or terminals malfunction Fuel tank pressure sensor malfunction Charcoal canister malfunction CV solenoid valve malfunction Evaporative chamber malfunction PCM malfunction

System Wiring Diagram

Not applicable

Function Explanation (DTC Detection Outline)

The PCM detects the pressure of the fuel tank based on the fuel tank pressure sensor signal. The PCM determines a fuel tank pressure sensor signal error based on the condition in which the fuel tank pressure sensor voltage continues to be the specified value or more, and stores a DTC.

Repeatability Verification Procedure

Switch the ignition off.

Leave the vehicle for 2 hours or more.

Start the engine and leave it idling for 1 min.

PID Item/Simulation Item Used In Diagnosis

PID/DATA monitor item table


Item	Definition	Unit	Condition/Specification
AAT	Ambient air temperature	°C, °F	Displays ambient air temperature
FTP	Fuel tank pressure	Pa {KPa} {MPa}, mBar {Bar}, psi, in H20	Displays fuel tank pressure
FTP	Fuel tank pressure	V	Fuel tank pressure is equal to barometric pressure: Approx. 2.6 V

Function Inspection Using M-MDS


STEP	INSPECTION	RESULTS	ACTION
1	PURPOSE: VERIFY RELATED REPAIR INFORMATION AVAILABILITY Verify related Service Bulletins and/or on-line repair information availability. Is any related repair information available?	Yes	Perform repair or diagnosis according to the available repair information. If the vehicle is not repaired, go to the next step.
1		No	Go to the next step.
2	PURPOSE: RECORD VEHICLE STATUS AT TIME OF DTC DETECTION TO UTILIZE WITH REPEATABILITY VERIFICATION Has the FREEZE FRAME DATA (Mode 2)/snapshot data been recorded?	Yes	Go to the next step.
2		No	Record the FREEZE FRAME DATA (Mode 2)/snapshot data on the repair order, then go to the next step. NOTE: Recording can be facilitated using the screen capture function of the PC.
3	PURPOSE: VERIFY IF FUEL TANK PRESSURE SENSOR HAS MALFUNCTION Perform the Pending Trouble Code Access Procedure and DTC Reading Procedure. (See ON-BOARD DIAGNOSTIC TEST [SKYACTIV-G 2.5].) Is the PENDING CODE/DTC P0452:00, P0453:00 or P0454:00 also present?	Yes	The possibility of a fuel tank pressure sensor malfunction is high. Go to the applicable PENDING CODE or DTC inspection. (See DTC P0452:00 [SKYACTIV-G 2.5].) (See DTC P0453:00 [SKYACTIV-G 2.5].) (See DTC P0454:00 [SKYACTIV-G 2.5].)
3		No	Go to the next step.
4	PURPOSE: INSPECTION OF CLOGGING BETWEEN FUEL TANK PRESSURE SENSOR AND FUEL TANK Perform the Pending Trouble Code Access Procedure and DTC Reading Procedure. (See ON-BOARD DIAGNOSTIC TEST [SKYACTIV-G 2.5].) Is the PENDING CODE/DTC P144A:00 also present?	Yes	The possibility of clogging between fuel tank pressure sensor and fuel tank is high. Go to the applicable PENDING CODE or DTC inspection. (See DTC P144A:00 [SKYACTIV-G 2.5].)
4		No	Go to the next step.
5	PURPOSE: VERIFY IF CV SOLENOID VALVE HAS MALFUNCTION Perform the Pending Trouble Code Access Procedure and DTC Reading Procedure. (See ON-BOARD DIAGNOSTIC TEST [SKYACTIV-G 2.5].) Is the PENDING CODE/DTC P0446:00 also present?	Yes	The possibility of a CV solenoid valve malfunction is high. Go to the applicable PENDING CODE or DTC inspection. (See DTC P0446:00 [SKYACTIV-G 2.5].)
5		No	Go to the next step.
6	PURPOSE: VERIFY IF FUEL TANK PRESSURE IS STUCK TO EITHER LOW OR HIGH PRESSURE SIDE Start the engine and idle it. Access the FTP PID using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [SKYACTIV-G 2.5].) Is the FTP PID value 0.424 kPa {0.00432 kgf/cm², 0.0615 psi} or more?	Yes	The possibility that the fuel tank pressure is stuck to the high pressure side is high. Go to the next step.
6		No	The possibility that the fuel tank pressure is stuck to the low pressure side is high. Go to the troubleshooting procedure to perform the procedure from Step 3.
7	PURPOSE: VERIFY IF MALFUNCTION CAUSE IS FREEZING OF FUEL TANK PRESSURE SENSOR BY VERIFYING AMBIENT TEMPERATURE Start the engine and idle it. Access the AAT PID using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [SKYACTIV-G 2.5].) Is the AAT PID value 0 °C {32 °F} or less?	Yes	The possibility of a malfunction caused by freezing of the fuel tank pressure sensor is high. Go to the troubleshooting procedure to perform the procedure from Step 1.
7		No	Go to the troubleshooting procedure to perform the procedure from Step 2.

Troubleshooting Diagnostic Procedure

Intention of troubleshooting procedure

Step 1

Visually verify that there are no traces of freezing on the fuel tank pressure sensor.

Step 2

Inspect the charcoal canister for clogging.

Step 3

Perform a unit inspection of the CV solenoid valve.

Step 4

Verify that there is no breakage or clogging in the evaporative hose.

Step 5

Inspect the evaporative chamber for clogging.

Step 6

Perform a unit inspection of the fuel tank pressure sensor.

Step 7—8

Verify that the primary malfunction is resolved and there are no other malfunctions.


STEP	INSPECTION	RESULTS	ACTION
1	PURPOSE: VISUALLY VERIFY THAT THERE ARE NO TRACES OF FREEZING ON THE FUEL TANK PRESSURE SENSOR Visually inspect for fuel tank pressure sensor. Can traces of freezing be verified on the fuel tank pressure sensor?	Yes	Evaporative gas freezes when the ambient temperature is low, and it is highly possible that the fuel tank pressure sensor measurement is affected because the vehicle was not refueled appropriately. Replace the fuel, then go to Step 7.
1		No	Go to Step 6.
2	PURPOSE: INSPECTION OF CHARCOAL CANISTER FOR CLOGGING Inspect for clogging in the charcoal canister. (See CHARCOAL CANISTER INSPECTION [SKYACTIV-G 2.5].) Is there any malfunction?	Yes	Replace the charcoal canister, then go to Step 7. (See CHARCOAL CANISTER REMOVAL/INSTALLATION [SKYACTIV-G 2.5].)
2		No	Go to the next step.
3	PURPOSE: DETERMINE INTEGRITY OF CV SOLENOID VALVE Inspect the CV solenoid valve. (See CANISTER VENT (CV) SOLENOID VALVE INSPECTION [SKYACTIV-G 2.5].) Is there any malfunction?	Yes	Replace the CV solenoid valve, then go to Step 7. (See CANISTER VENT (CV) SOLENOID VALVE REMOVAL/INSTALLATION [SKYACTIV-G 2.5].)
3		No	Go to the next step.
4	PURPOSE: INSPECTION OF EVAPORATIVE HOSE FOR BREAKAGE OR CLOGGING Inspect for breakage or clogging in the evaporative hose (hose between evaporative chamber and atmosphere). Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results, then go to Step 7.
4		No	Go to the next step.
5	PURPOSE: INSPECTION OF EVAPORATIVE CHAMBER FOR CLOGGING Inspect for clogging in the evaporative chamber. (See EVAPORATIVE CHAMBER INSPECTION [SKYACTIV-G 2.5].) Is there any malfunction?	Yes	Replace the evaporative chamber, then go to Step 7. (See EVAPORATIVE CHAMBER REMOVAL/INSTALLATION [SKYACTIV-G 2.5].)
5		No	Go to the next step.
6	PURPOSE: DETERMINE INTEGRITY OF FUEL TANK PRESSURE SENSOR Inspect the fuel tank pressure sensor. (See FUEL TANK PRESSURE SENSOR INSPECTION [SKYACTIV-G 2.5].) Is there any malfunction?	Yes	Replace the charcoal canister, then go to the next step. (See CHARCOAL CANISTER REMOVAL/INSTALLATION [SKYACTIV-G 2.5].)
6		No	Go to the next step.
7	PURPOSE: VERIFICATION OF VEHICLE REPAIR COMPLETION Reconnect all the removed parts. Clear the DTC from the PCM memory using the M-MDS. (See CLEARING DTC [SKYACTIV-G 2.5].) Implement the repeatability verification procedure. (See Repeatability Verification Procedure.) Perform the DTC Reading Procedure. (See ON-BOARD DIAGNOSTIC TEST [SKYACTIV-G 2.5].) Is the same DTC present?	Yes	Repeat the inspection from Step 1 of the troubleshooting diagnostic procedure. If the malfunction recurs, replace the PCM. (See PCM REMOVAL/INSTALLATION [SKYACTIV-G 2.5].) Go to the next step.
7		No	Go to the next step.
8	PURPOSE: VERIFY IF THERE IS ANY OTHER MALFUNCTION Is any other DTC or pending code stored?	Yes	Go to the applicable DTC inspection. (See DTC TABLE [SKYACTIV-G 2.5].)
8		No	DTC troubleshooting completed.

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