P1451 - FAULT CODE - OBD2

P1451 FORD, LINCOLN, MERCURY: EVAP CONTROL SYSTEM CANISTER VENT SOLENOID CIRCUIT MALFUNCTION

The evaporative emission control system (EVAP) purge solenoid is installed in the emission control of modern vehicles. The purpose of the EVAP system is to reduce pollution levels that come from the evaporative emissions produced by the vehicle’s fuel, which are released as vapors. This system catches and recirculates these vapors so that they can be used later as fuel for the engine to reduce environmental pollution.

The canister solenoid purges the EVAP system and plays the role of a switch that allows steam to enter the engine. The entire EVAP system process is monitored by the PCM or better known Powertrain Control Module.  In one of these checks, the solenoid circuit is monitored for possible electrical faults. If the signal is not within the allowed range for a canister vent duty cycle specified by the PCM, a DTC will be set to warn of the situation.

The OBDII code P1451 shows that the EVAP solenoid is not working properly, causing EVAP leakage.

• Check Engine light ON.
• Difficult start of the engine.
• Irregular engine operation at idle.

Reasons to set the P1451 OBD2 diagnostic code:

• The EVAP vent solenoid wiring or connectors may be in poor condition.
• The solenoid may be faulty.
• The PCM may be

Steps to troubleshoot the P1451 OBDII fault code :

• Consult the TSB (Technical Service Bulletins).
• Inspect all wiring as well as connectors that relate to the EVAP Repair conditions such as corrosion burns or wear.
• Make voltage tests to the ventilation solenoid circuit following the manufacturer's recommendations. The values obtained should be compared with those specified and if discrepancies are detected, make the respective corrections.
• Check if the EVAP solenoid resistance is within the parameters for proper operation. An out-of-range resistance requires replacement.