Fix Ford P1451: Mechanic’s solutions that WORKED

The code P1451: EVAP Control System Canister Vent Solenoid Circuit Malfunction (FORD) indicates a malfunction in the circuit of the EVAP canister vent solenoid, a key component in the vehicle’s emissions control system. This issue is typically caused by problems with the solenoid itself, wiring and connector issues, or faults within the broader EVAP system.

Ford P1451 quick overview

Meaning	P1451: EVAP Control System Canister Vent Solenoid Circuit Malfunction
Is it serious?	Yes, it can affect the vehicle’s emissions system and fuel efficiency.
Possible causes	– Faulty EVAP canister vent solenoid – Damaged, corroded, or disconnected wiring and connectors – Faults in the EVAP system or fuel tank components – Issues with the Powertrain Control Module (PCM)
How to diagnose?	Inspect Wiring and Connectors: Check for damage, corrosion, or disconnections in the wiring. Test Solenoid Operation: Perform functional tests on the canister vent solenoid. Check Power and Ground: Verify all power and ground connections to the solenoid are secure. Inspect Fuel Tank Components: Look for faults in the fuel tank level sensor and other related parts. Consider PCM Issues: Evaluate the PCM for faults or the need for reprogramming. Perform Voltage Drop Test: Conduct this test to identify resistance in the circuit.

This error code means there’s a problem with the part of your car that controls the vapors from the fuel system. It’s important for controlling pollution and making sure your car runs efficiently. Usually, it’s a sign that there’s something wrong with the electrical parts connected to this system, or the valve that lets these vapors out might be faulty. Fixing it will help your car pass emissions tests and could improve your fuel mileage.

How to fix Ford P1451 – learn from mechanics

I looked into Ford P1451 service cases at iatn.com website where in the private forums the mechanics seek advice from other mechanics. I looked up a bunch of cases to help you decide how to fix your issue and see what would a real mechanic do to solve it.

Case #1: Ford

Vehicle Information

• 2001 Ford E-150 Econoline, 5.4L

Issue + Repair History

• MIL Lamp on
• Code: P1451 (EVAP Canister Vent Solenoid Fault)
• Replaced PCM, canister vent solenoid, FTPT sensor, power, and ground wires for the solenoid

Other OBD2 Codes + Test Results

• P1451- Evap canister vent solenoid fault

Suggestions to Fix Issue

• Check for open or short in the Purple/White wire from the canister vent solenoid to PCM pin 67
• Verify voltage at the vent solenoid
• Test Red and Yellow wire for power at vent valve
• Command vent valve on and test for ground on Violet and White wire
• Inspect vent solenoid connector pins for corrosion or spreading

Final Fix

• Original canister vent control solenoid was reinstalled after finding the replacement from Ford was defective
• The reinstallation of the old solenoid resolved the code issue

Case #2: Ford

Vehicle Information

• 1996 Ford Explorer XL, 4.0L

Issue + Repair History

• MIL Lamp on after Heater/AC plenum replacement due to a broken temp. blend door
• Codes: P0453 and P1451

Other OBD2 Codes + Test Results

• P0453- Fuel Tank Pressure Sensor Circuit High
• P1451- EVAP Canister Vent Solenoid Circuit Out of Limit

Suggestions to Fix Issue

• Check for a vacuum leak in the EVAP system
• Verify if PCM was disconnected during repair and check for damaged pins or bad connections
• Inspect wiring harness connectors, especially behind the right kick panel

Final Fix

• Reconnected a wiring harness connector behind the right kick panel that was not properly connected after the Heater/AC repair. This resolved the MIL issue.

Case #3: Ford

Vehicle Information

• 2001 Ford Escape XLT, 3.0L

Issue + Repair History

• MIL Lamp on
• Code: P1451 (EVAP Canister Vent Solenoid Circuit Fault)
• Replaced EVAP canister vent solenoid

Other OBD2 Codes + Test Results

• P1451- EVAP Canister Vent Solenoid Circuit Fault

Suggestions to Fix Issue

• Check gas cap for proper locking and sealing
• Inspect for cracked vapor line between vent solenoid and VMV
• Perform smoke test for leaks
• Check wiring between solenoid and PCM for faults
• Consider PCM fault if wiring is intact

Final Fix

• Dealer repair fixed the issue, identified as a bad wire somewhere, specific details not disclosed

Case #4: Ford

Vehicle Information

• 2000 Ford Taurus SE, 3.0L

Issue + Repair History

• MIL Lamp on
• Code: P1451 (EVAP Canister Vent Solenoid Circuit Malfunction)
• Code returns immediately after clearing
• Replaced vent solenoid, but the code persisted

Other OBD2 Codes + Test Results

• P1451- Evap canister vent solenoid circuit malfunction

Suggestions to Fix Issue

• Check for wiring problems, especially corrosion behind the LF inner splash shield
• Perform a voltage drop test on the circuit
• Consider the possibility of a PCM issue
• Monitor ECU control during EVAP solenoid activation

Final Fix

• Identified wiring corrosion behind the LF inner splash shield as the cause
• Repairing the corroded wiring resolved the issue

Case #5: Ford

Vehicle Information

• 2000 Ford Ranger XL, 3.0L

Issue + Repair History

• MIL Lamp on
• Codes: P0176 (Fuel Compensation Module Circuit Problem), P0460 (Fuel Tank Level Sensor), P1451 (Purge Solenoid Problem)
• Replaced fuel compensation module

Other OBD2 Codes + Test Results

• P0176- Fuel Compensation Module Circuit Problem
• P0460- Fuel Tank Level Sensor
• P1451- Purge Solenoid Problem

Suggestions to Fix Issue

• Rigorous testing of the fuel sender float apparatus
• Check the wiring input from the sender to the compensation module
• Inspect interior fuse box for a blown fuse
• Check the connector underneath the car, under the driver’s seat, for corrosion
• Check the sending unit in the tank
• Consider replacing the purge flow sensor

Final Fix

• Found and repaired corroded wires under the seat leading to underneath the vehicle
• Four pins were rotted off, repairing them fixed the issue

Common Advice	Diagnostic Step Description for Ford Vehicles
Check Wiring and Connectors	Inspect wiring and connectors for corrosion, especially in areas prone to moisture or damage.
Verify Power and Ground to Components	Ensure all power and ground connections to related components, like the EVAP system, are secure and functional.
Test Solenoids and Sensors	Perform functional tests on solenoids and sensors related to the code, like the canister vent solenoid and fuel tank pressure sensor.
Perform Voltage Drop Test	Conduct a voltage drop test to identify any resistance in the circuit that might be causing the issue.
Inspect Fuel Tank and Evap System	Check the fuel tank components, including the level sensor and any EVAP system parts for faults or damage.
Consider PCM or Module Issues	Rule out any potential issues with the Powertrain Control Module (PCM) or related modules.
Perform Visual Inspection for Damage	Conduct a thorough visual inspection for any physical damage or wear that could be impacting the system.
Use OEM Parts for Replacements	When replacing parts like solenoids or sensors, use original equipment manufacturer parts for compatibility and reliability.