DTC P144A:00 [SKYACTIV-G 2.5]

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2014 - Mazda6 - Engine

DTC P144A: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	Evaporator system: clogging between fuel tank and fuel tank pressure sensor
DETECTION CONDITION	Determination conditions	The following conditions are all met while the vehicle is being driven: If negative pressure is inducted to the fuel tank via the intake manifold by the operation of the purge solenoid valve with the fuel tank in a sealed condition and the target negative pressure is reached within a shorter period of time than the estimated time. When the barometric pressure in the fuel tank is fixed and the purge solenoid valve is opened/closed, the negative pressure fluctuation in the fuel tank generates negative pressure exceeding the threshold.
	Preconditions	Period ignition is switched off before engine is started: 120 min or more Engine coolant temperature at engine start: 1.67—43.33 °C {35.1—109.9 °F}^1 Time elapsed from engine start: 5.5—90 min* Fuel level in fuel tank: 10—90 %^1 Desired ambient air temperature: 4.4—43.3 °C {40—109 °F}^1 Barometric pressure: 72.23 Pa {7.365 kgf/m², 0.01048 psi} or more^1 Charging efficiency: 3—65 %^1 Vehicle speed: 64—144.8 km/h {40.00—89.97 mph}^1 Purge flow amount: 15 l/min or more* ^*1: Value can be verified by displaying PIDs using M-MDS
	Malfunction determination period	75 s period
	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	Erratic signal to PCM Fuel tank pressure sensor signal malfunction Fuel gauge sender unit malfunction Fuel tank pressure sensor malfunction Clogging between fuel tank and fuel tank pressure sensor Fuel shut-off valve malfunction Rollover valve malfunction Purge solenoid valve malfunction PCM malfunction

System Wiring Diagram

Not applicable

Function Explanation (DTC Detection Outline)

The PCM closes the purge solenoid valve and CV solenoid valve while the vehicle is being driven and seals the fuel tank. Then, gas in the fuel tank is inducted into the intake manifold and the pressure in the fuel tank is decreased by opening the purge solenoid valve, and the pressure change in the fuel tank is measured using the fuel tank pressure sensor. If the pressure in the fuel tank decreases below the target negative pressure during the specified period from the pressure measurement (malfunction determination time (1)), positive pressure is inducted to the fuel tank via the intake manifold by closing the purge solenoid valve and opening the CV solenoid valve. After positive pressure is inducted to the fuel tank, the fuel tank is sealed, opening/closing of the purge solenoid valve is performed repeatedly, and the pressure change in the fuel tank is monitored at that time (malfunction determination time (2)). If the amount of pressure change veers towards negative pressure exceeding the malfunction determination threshold, the PCM determines that there is clogging between the fuel tank pressure sensor and fuel tank, and stores a DTC.

Repeatability Verification Procedure

Set the remaining fuel quantity in the fuel tank between 30—85 %.

Verify that OBD-II information (such as FREEZE FRAME DATA (Mode 2)) has been obtained and recorded.

Clear the DTC from the PCM memory using the M-MDS. (See CLEARING DTC [SKYACTIV-G 2.5].)

Start the engine and switch the ignition off after 5 s have elapsed.

Leave the vehicle for 6 hours or more.

Start the engine and leave it idling for 2 min.

Drive the vehicle for 30 min at a speed of 50 km/h {31 mph} or more (to increase temperature in fuel tank and generate evaporative gas).

NOTE:

If driving the vehicle for 30 min at a speed of 50 km/h {31 mph} or more is not feasible, the vehicle can be driven for a continuous 15 min or more with the engine coolant temperature at 80 °C {176 °F} or more.

Stop the engine.

Leave the vehicle for 1 hours or more.

PID Item/Simulation Item Used In Diagnosis

PID/DATA monitor item table


Item	Definition	Unit	Condition/Specification
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

Simulation item table


Item	Definition	Unit	Operation
EVAPCP	Purge solenoid valve control signal	%	Changes % and forcibly drives/stops purge solenoid valve.
EVAPCV	CV solenoid valve control signal	Off/On	Selects Off/On to forcibly drive/stop the CV solenoid valve.

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 GAUGE SENDER UNIT 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 P0460:00, P0461:00, P0462:00 or P0463:00 also present?	Yes	Perform the DTC troubleshooting for the fuel gauge sender unit first because the fuel gauge sender unit cannot detect the fuel tank level and determines that a malfunction is occurring. (See DTC P0460:00 [SKYACTIV-G 2.5].) (See DTC P0461:00 [SKYACTIV-G 2.5].) (See DTC P0462:00 [SKYACTIV-G 2.5].) (See DTC P0463:00 [SKYACTIV-G 2.5].)
3		No	Go to the next step.
4	PURPOSE: VERIFY FUEL TANK PRESSURE SENSOR MEASURED CORRECTLY Start the engine and idle it. Access the following simulation items using the M-MDS: (See ON-BOARD DIAGNOSTIC TEST [SKYACTIV-G 2.5].) EVAPCP EVAPCV Change to the following conditions using the simulation function. EVAPCP: 100 % EVAPCV: On Access the FTP PID using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [SKYACTIV-G 2.5].) Does the negative pressure change when racing the engine?	Yes	The fuel tank pressure sensor measures correctly. Go to the next step.
4		No	The possibility of a fuel tank pressure sensor malfunction is high. Go to the troubleshooting procedure to perform the procedure from Step 1.
5	PURPOSE: VERIFY IF PURGE SOLENOID VALVE IS STUCK OPEN Perform the following procedure to induct barometric pressure to the fuel tank. Access the following simulation items using the M-MDS: (See ON-BOARD DIAGNOSTIC TEST [SKYACTIV-G 2.5].) EVAPCP EVAPCV Change to the following conditions using the simulation function. EVAPCP: 0 % EVAPCV: Off Access the FTP PID using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [SKYACTIV-G 2.5].) NOTE: The displayed PID value is as follows: BARO: approx. 2.6 V (barometric pressure) Perform the following procedure to force drive the CV solenoid valve. Access the following simulation items using the M-MDS: (See ON-BOARD DIAGNOSTIC TEST [SKYACTIV-G 2.5].) EVAPCP EVAPCV Change to the following conditions using the simulation function. EVAPCP: 0 % EVAPCV: On Access the FTP PID using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [SKYACTIV-G 2.5].) Is the FTP PID value negative pressure?	Yes	The possibility of a stuck purge solenoid valve open is high. Go to the troubleshooting procedure to perform the procedure from Step 2.
5		No	The possibility of clogging between fuel tank pressure sensor and fuel tank is high. Go to the troubleshooting procedure to perform the procedure from Step 3.

Troubleshooting Diagnostic Procedure

Intention of troubleshooting procedure

Step 1

Perform a PCM input signal part-related inspection.

Step 2

Perform a unit inspection of the purge solenoid valve.

Step 3—5

Inspect for clogging between fuel tank pressure sensor and fuel tank.

Step 6—7

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


STEP	INSPECTION	RESULTS	ACTION
1	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 Step 6. (See CHARCOAL CANISTER REMOVAL/INSTALLATION [SKYACTIV-G 2.5].)
1		No	Go to the next step.
2	PURPOSE: DETERMINE INTEGRITY OF PURGE SOLENOID VALVE Inspect the purge solenoid valve. (See PURGE SOLENOID VALVE INSPECTION [SKYACTIV-G 2.5].) Is there any malfunction?	Yes	Replace the purge solenoid valve, then go to Step 6. (See PURGE SOLENOID VALVE REMOVAL/INSTALLATION [SKYACTIV-G 2.5].)
2		No	Go to the next step.
3	PURPOSE: VERIFY IF THERE IS CLOGGING BETWEEN FUEL TANK PRESSURE SENSOR AND FUEL TANK Verify the following passage hoses, pipe connection condition, and that there is no clogging. Between fuel tank pressure sensor and fuel shut-off valve Is there any poor connection or clogging?	Yes	Repair or replace the malfunctioning part according to the inspection results, then go to Step 6.
3		No	Go to the next step.
4	PURPOSE: DETERMINE INTEGRITY OF FUEL SHUT-OFF VALVE Inspect the fuel shut-off valve. (See FUEL TANK INSPECTION [SKYACTIV-G 2.5].) Is there any malfunction?	Yes	Replace the fuel tank, then go to Step 6. (See FUEL TANK REMOVAL/INSTALLATION [SKYACTIV-G 2.5].)
4		No	Go to the next step.
5	PURPOSE: DETERMINE INTEGRITY OF ROLLOVER VALVE Inspect the rollover valve. (See FUEL TANK INSPECTION [SKYACTIV-G 2.5].) Is there any malfunction?	Yes	Replace the fuel tank, then go to the next step. (See FUEL TANK REMOVAL/INSTALLATION [SKYACTIV-G 2.5].)
5		No	Go to the next step.
6	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.
6		No	Go to the next step.
7	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].)
7		No	DTC troubleshooting completed.

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