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This code usually ends up in replacing the Evap purge flow sensor or the canister purge solenoid.
P1443 EVAP Purge Flow System Malfunction
Possible Causes Setting Conditions
* EVAP connector is damaged (check pins for damage, and for moisture)
* EVAP canister purge valve has failed
* PCM has failed
Remove the vacuum line from the charcoal canister so that it's open to the atmosphere.
Back probe the Black/Light Green (BK/LG) wire at the purge flow sensor with a voltmeter.
Start the engine
. Use a jumper wire to ground the Grey/Yellow (GY/Y) wire at the canister purge solenoid.
With the solenoid grounded, there should be good vacuum on the line that would go to the canister and the purge flow sensor voltage should increase by 1.0-1.5v from where it started.
If there is good vacuum through the hose, but the purge flow sensor voltage does not increase as it should, replace the purge flow sensor.
If there is not good flow through the vacuum hose, verify there is good vacuum to the canister purge solenoid. If so, suspect a mechanically faulty solenoid.
The Purge Flow Sensor is located at the LH front of the engine compartment. PURPOSE
The Purge Flow Sensor (PFS)
is used to monitor the Canister Purge (CANP)
solenoid operation during the OBD II Evaporative Emission Test. OPERATION
The PFS monitors the vapor flow through the CANP solenoid and changes the PFS input signal to the Powertrain Control Module (PCM)
based on flow or no flow conditions. The PCM monitors this signal and gives an output signal to the CANP solenoid, based on the flow conditions. PURPOSE
- The Evaporative Canister Purge Solenoid controls the flow of vapors (purging) from the carbon canister to the intake manifold during various engine operating modes. The Evaporative Canister Purge Solenoid is a normally closed valve in the evaporative emission system.
- The operation of the Evaporative canister purge solenoid is controlled by the Powertrain Control Module (PCM) . When the engine is off, the Evaporative Canister Purge Solenoid is not energized and is in a closed, non-flowing condition.
- When the engine is running, the PCM reads engine rpm, engine load, engine temperature and other variables, and decides the proper time for the engine to accept fuel vapors.
- When this occurs, the PCM energizes the fuel Evaporative Canister Purge Solenoid, allowing flow from the fuel vapor canister to the intake manifold. The vapors are then consumed in the engine. This action "purges" the fuel vapor canister of fuel vapors.