Safety Warning

DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.

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HOMESERVICE MANUALSMAZDA2006B4000 BASE, AUTOMATICREPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCESYSTEMENGINE SYMPTOM TROUBLESHOOTING - (3 OF 5)DTC APPLICATION CHART - POWERTRAIN CONTROL MODULE (PCM)EVAP SYSTEM MALFUNCTION

2006 Mazda B4000 Base, Automatic

EVAP System Malfunction

2006 Mazda B4000 Base, AutomaticSECTION EVAP System Malfunction

P0451, P0461 DETECTION CONDITION & POSSIBLE CAUSES

P0451, P0461

EVAP SYSTEM MALFUNCTION

DETECTION CONDITION

P0451 indicates the fuel tank pressure changes greater than 3.48 Kpa (14 in-H₂ O) in 0.10 seconds (sensor circuit noisy).
P0461 indicates the fuel level input noisy.

POSSIBLE CAUSE

Intermittent open or short in the FTP sensor circuit (P0451)
Intermittent open or short in the FLI circuit (P0461)

HINT

Fuel Tank Pressure Sensor Description

Used to measure the fuel tank pressure during the EVAP monitor test and to control excessive fuel tank pressure by forcing the system to purge.

Fuel Level Input Description

Indicates the fuel level in the tank.
Hard wire signal input to the powertrain control module (PCM) from the fuel pump (FP) module.

P0451, P0461 DIAGNOSTIC PROCEDURE

P0451, P0461		EVAP SYSTEM MALFUNCTION
STEP	INSPECTION		ACTION
1	PCM QUICK TEST Was the PCM quick test performed?	Yes	If any other DTG is present, Go to applicable DTC Troubleshooting. See DIAGNOSTIC TROUBLE CODE (DTC) INDEX - POWERTRAIN CONTROL MODULE (PCM) . If only DTC P0451 and/or P0461 are present, see GENERAL PINPOINT TEST 4: INTERMITTENT .
1	PCM QUICK TEST Was the PCM quick test performed?	No	Perform PCM quick test. See PCM QUICK TEST .

RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.
• Brakes feel soft, pull hard to one side, or make grinding noises.
• The engine overheats, stalls repeatedly, or misfires under load.
• You are missing required tools, torque specs, or safe lifting equipment.
• You are not confident in the next step or safety outcome.