Engine check light on. Code 1443. No driveability issues. Same problem 2 months ago, removed purge control valve, sensor, cleaned and checked valve, replaced hoses, no engine check light. Now all checks good except no voltage to Purge control valve. Have Ford factory service manual, but not the emissions manual. What fuse is this on? Can the valve just be eliminated from the system? Truck idles poorly with manifold hose removed, so suspect the system restricts airflow somehow. Thanks in advance for any assistance.

DCS

 

Further diagnosis has revealed purge control valve connector "hot" is fine however no ground thru connector. Also removed purge control valve from system (with sensor inline between carbon can and manifold), idles poor, similar to tube removed from manifold. Does purge control valve switch on-off during engine operation or is it always open? Is purge contol valve controlled with a negative switching system? Hot always hot? Again, thanks for any info in advance... DCS

 

This is from the Ford emissions manual..........

The (EVAP) Purge Flow system consists of a fuel tank, fuel filler cap, fuel vapor valve, EVAP canister, EVAP canister purge valve, purge flow (PF) sensor, intake manifold hose assembly, powertrain control module (PCM) and connecting wires and fuel vapor hoses. Operation of the system is as follows (Figure 118) :

The EVAP Purge Flow system uses inputs from the engine coolant temperature (ECT) sensor, the intake air temperature (IAT) sensor, the throttle position (TP) sensor, the mass air flow (MAF) sensor and the vehicle speed sensor (VSS) to provide information about engine operating conditions to the PCM. The conditions necessary to activate the EVAP Purge Flow system is that the engine must be warm, stable, running at moderate load, and at open or part throttle position. The power relay provides vehicle power (VPWR) to the PCM, EVAP canister purge valve and PF sensor. The PCM deactivates the EVAP Purge Flow during idle, closed throttle or whenever a failure is detected in the EVAP canister purge valve, PF sensor or evaporative emission purge flow required input.
The PCM calculates the desired amount of purge vapor flow to the intake manifold for a given engine condition. The PCM can then output the proper duty cycle signal to the EVAP canister purge valve.
The EVAP canister purge valve is a normally closed valve (duty cycle at 0%), but receives a duty cycle signal (0% to 100%) from the PCM during various operating modes. The EVAP canister purge valve uses that signal from the PCM and responds by controlling the flow of vapors (purging) from the EVAP canister to the intake manifold.
The PF sensor is used to determine if fuel vapor is flowing to the intake manifold through the fuel vapor hose from the EVAP canister.




The canister purge solenoid should have 12V to it when the ignition is on. The power to it comes from the EEC relay and the PCM switches it on and off, on the ground side. Most problems I've seen with this sytem were the purge flow sensor not working properly. Resistance of the PF sensor should be 40-230 ohms. Resistance of the PF solenoid should be 30-90 ohms.
Let me know if this helps or not.

 

Awesome, thanks for the detailed reply! Happy new year. No dice on a PF sensor today from aftermarket parts house. Will have to wait 'till tomorrow. I'll also try to see if I can get a ground from the solenoid connector under load. The solenoid checks good when 12v is applied. So if it is also getting the signal to open it has got to be the sensor... Thanks again!! DCS

 

PF sensor replaced. No engine check light. Subject vehicle is repaired and RETURNED TO SERVICE!! Thanks for the Help!!

 

Thanks you guys, good question and reply. That was a help to me.

Dave Powell