Check Engine light has been on a couple of weeks now. Disconnected battery and code went away, but returned in less than 24 hours. Took it to Autozone and the code came up as P1445 -Purge Flow Sensor Circuit High Input

I followed some threads for P1443 which is very similar, but coudn't find anything on P1445. Looking for some assistance...should I use the same approach as the 1443 since they are very similiar. I need to pass emissions testing this month, so I need to take care of asap. Thanks in advance. -BH

 

Welcome to FTE bobber1.
Just bumping the post to see if someone knows the correct answer.

 

Here you go, thanks for bumping it BTT dealford.

HW33 DTC P1445: CHECK PF SENSOR HIGH VOLTAGE TO PCM
Continuous Memory Diagnostic Trouble Code (DTC) P1445 indicates that Self-Test has detected a PF sensor circuit input above the maximum.

Possible causes:

PF shorted to VPWR.
PF open circuit.
PWR GND open circuit.
Damaged purge flow (PF) sensor.
Damaged PCM.
Disconnect PF sensor.
Check for loose pins or broken wires by pulling moderately on the PF and PWR GND circuits at PF sensor harness connector.
Repair as necessary.
Reconnect PF sensor.
Connect scan tool.
Key on, engine off.
Note: PF sensor input to the PCM range is 0.40 to 4.80 volts.

Access EVAPPF PID.
Key off.
Was EVAPPF PID voltage greater than 4.80 volts?
Yes No
GO to HW34 . Fault is an intermittent DTC P1445. GO to HW39 .

HW34 CHECK VPWR RESISTANCE FOR SHORT TO PF CIRCUIT IN PF SENSOR
Key off.
Disconnect PF sensor.
Allow the vehicle and PF sensor to cool down or warm up to a room temperature 13°C to 27°C (55° F to 80°F) before taking a resistance measurement on the PF sensor. This can take 15 to 20 minutes.
Measure resistance between VPWR and PF pins on the PF sensor.
Is resistance between 40 and 230 ohms?
Yes No
GO to HW35 . REPLACE damaged PF sensor. RESTORE vehicle. GO to HW42 .

HW35 CHECK PF SENSOR VOLTAGE INPUT TO PCM
Key on, engine off.
Measure PF circuit voltage at PF sensor harness connector to battery negative post.
Key off.
Was voltage greater than 10.5 volts?
Yes No
GO to HW36 . GO to HW37 .

HW36 CHECK PF CIRCUIT FOR SHORT TO VPWR IN HARNESS
Install breakout box, leave PCM disconnected.
Key on, engine off.
Measure resistance between PCM test pin 11 and PCM test pins 24 or 103.
Is the voltage greater than 10.5 volts?
Yes No
REPAIR short circuit. RESTORE vehicle. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test . REPLACE damaged PCM. RESTORE vehicle. RERUN Quick Test .

HW37 CHECK PF CIRCUIT FOR OPEN IN HARNESS
Install breakout box, leave PCM disconnected.
Measure resistance of PF circuit between PCM test pin 11 and PF sensor harness connector.
Is the resistance less than 5.0 ohms?
Yes No
GO to HW38 . REPAIR open circuit. RESTORE vehicle. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test .

HW38 CHECK PWR GND CIRCUIT FOR OPEN IN HARNESS
Measure resistance of PWR GND circuit between PCM test pin 24 or 103 and PF sensor harness connector.
Is the resistance less than 5.0 ohms?
Yes No
REPLACE damaged PCM. RESTORE vehicle. RERUN Quick Test . REPAIR open circuit. RESTORE vehicle. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test .

 

Thanks Ken. Looks like the trouble was with the PF Sensor. I changed it out and have not had the problem since. Thanks again.
-Bobber

 

Glad to hear things are good now.

 

I have the same error code P1445. You refer to a PF sensor. I cannot find any listing of a part called purge flow sensor. Does it have another name? Is that the same as MAF sensor?

 

Not that I'm familar with another name, have you tried to get it at Ford. No it's not the MAF and you don't have to replace the O2 either.

 

It is called the purge control valve and is located on the vacuum hose coming from the charcoal cannister going to the manifold. There should also be another valve called a thermistor next to it. They both have wires running to them and should be easy to find.

 

Ken00 was nice enough to post the troubleshooting steps for the P1445.
One of the first steps ends with "Fault is an intermittent DTC P1445. GO to HW39 ."

But step HW39 was not posted. Does anyone know what the HW39 step is? Is it to replace the sensor ?

Thanks,
Tom

 

I had the same trouble, the purge flow valve and the thermister and all associated pre formed vacuume lines are sold as a kit from the dealer. Here in Canada it was $90 at a local Mazda dealer. The Ford Dealer wanted over $250 for it. Pay's to look around.

I was told by others on this forum to buy the kit and replace all the components. Did the trick for me.

 

Here's 39 to the end...

HW39 CHECK PURGE FLOW SENSOR CIRCUIT FOR INTERMITTENT PF OPEN OR VPWR SHORT
Key on, engine off.
Access EVAPPF PID.
Observe EVAPPF PID for an indication of a fault while performing the following:
Lightly tap on PF sensor; wiggle PF sensor connector and harness between sensor and PCM. A fault is indicated by a sudden change in EVAPPF PID voltage (greater than 4.80 volts).
Is a fault indicated?
Yes No
ISOLATE fault and REPAIR as necessary. RESTORE vehicle. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test . UNABLE to duplicate or identify fault at this time. GO to Pinpoint Test Step Z1 with the following data:

PF PID and a list of Possible causes.

HW40 DTC P0443: INSPECT EVAP CANISTER PURGE VALVE CIRCUIT FOR INTERMITTENT FAILURE
Continuous Memory Diagnostic Trouble Code (DTC) P0443 may indicate an EVAP canister purge valve circuit failure.

Possible causes:

Damaged EVAP canister purge valve.
EVAP CANISTER PURGE or VPWR circuit open.
Rerun KOEO, KOER Self-Tests and retrieve Continuous Memory DTCs.
Is DTC P0443 present in Continuous Memory Self-Test only?
Yes No
GO to HW41 . GO to HW1 .

HW41 CHECK EVAP CANISTER PURGE VALVE CIRCUIT INTERMITTENT OPEN OR SHORT
Install breakout box, leave PCM disconnected.
Measure resistance between PCM test pin 67 or PCM test pin 56 and PCM test pin 71, while performing the following:
Lightly tap on the EVAP canister purge valve and observe a resistance change.
Wiggle the EVAP canister purge valve connector and vehicle harness between the valve and the PCM, observe a resistance change.
Does the resistance reading change to below 30 ohms or above 90 ohms (vehicles with test pin 67) or above 38 ohms (vehicles with test pin 56)?
Yes No
ISOLATE fault and REPAIR as necessary. RESTORE vehicle. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test . UNABLE to duplicate or identify fault at this time. GO to Pinpoint Test Step Z1 with the resistance readingsand list of Possible causes.

HW42 VERIFICATION OF EVAPORATIVE EMISSION SYSTEM REPAIR USING ROTUNDA EVAPORATIVE EMISSION SYSTEM LEAK TESTER
Plug or tape atmospheric vent cap on EVAP canister (if applicable).
Remove fuel filler cap at fuel filler pipe.
Install Rotunda Evaporative Emission System Leak Tester 134-00056 or equivalent including the nitrogen or argon gas supply and pressure regulator.
Disconnect and plug fuel vapor hose to PF sensor (or EVAP canister purge valve on Ranger) from intake manifold at the intake manifold vacuum source.
Pressurize the EVAP system at 6.74 kPa (27 in-H 2 O) with tester.
Observe tester installation leak self-test for two minutes and then the EVAP system leak test.
Listen for a vacuum leak noise and check for substantial fuel vapor odors at isolated areas in the EVAP system.
Does the pressure applied to the EVAP system hold?
Yes No
REMOVE plug and RECONNECT fuel vapor hose from PF sensor (or EVAP canister purge valve) at intake manifold vacuum source. REMOVE EVAP System Leak Tester. REINSTALL fuel filler cap. TIGHTEN cap only one eighth turn so that cap initially clicks by sound or touch. COMPLETE PCM Reset to clear DTCs. Access EVAPPDC PID on scan tool. DRIVE vehicle (including a steady accelerator speed over 80 km/h (50 mph) until EVAPPDC PID shows 75 percent duty cycle). Then maintain approximate speed until duty cycle reaches zero percent. After additional two minute drive, bring vehicle to an idle. RERUN Quick Test . VERIFY a symptom no longer exists. GO to HW43 .

HW43 CHECK LOCATION OF EVAPORATIVE EMISSION SYSTEM PRESSURE LEAK
Systematically isolate area of potential pressure leak.
Close off pressure to EVAP system.
Disconnect and plug fuel vapor hose from fuel tank at EVAP canister.
Apply controlled pressure at 6.74 kPa (27 in-H 2 O to the EVAP system with the leak tester.
If pressure now holds, GO to the Powertrain/Engine Group, Evaporative Emissions Section in the Workshop Manual for EVAP canister diagnosis.
If system presure cannot hold, close pressure supply to system.
Disconnect and plug fuel vapor hose from EVAP canister at EVAP canister purge valve.
Again, apply controlled pressure to the EVAP system.
Does the pressure hold?
Yes No
REMOVE plugs. RECONNECT fuel vapor hose at EVAP canister. RETURN to Pinpoint Test Step HW14 to check EVAP canister purge valve integrity on Ranger or Pinpoint Test Step HW18 to check EVAP canister purge valve integrity on Mustang. REMOVE EVAP System Leak Tester. REINSTALL fuel filler cap. COMPLETE PCM Reset to clear DTCs. Access EVAPPDC PID on scan tool. DRIVE vehicle (including a steady accelerator speed over 80 km/h (50 mph) until EVAPPDC PID shows 75 percent duty cycle). Then maintain approximate speed until duty cycle reaches zero percent. After additional two minute drive, bring vehicle to an idle. RERUN Quick Test . VERIFY a symptom no longer exists. REMOVE plugs. CHECK for fuel vapor hose cracks or fuel vapor valve damage. EXAMINE and SECURE fuel vapor hose connections to components. REPAIR or REPLACE as necessary. REMOVE EVAP System Leak Tester. REINSTALL fuel filler cap. COMPLETE PCM Reset to clear DTCs. Access EVAPPDC PID on scan tool. DRIVE vehicle (including a steady accelerator speed over 80 km/h (50 mph) until EVAPPDC PID shows 75 percent duty cycle). Then maintain approximate speed until duty cycle reaches zero percent. After additional two minute drive, bring vehicle to an idle. RERUN Quick Test . VERIFY a symptom no longer exists.

 

Had the same prob and you can only get it (purge valve sensor) at the dealer cause it's an emission part and the auto stores say they don't carry emmision equipment.
At least round here anyways. Cost something like 80 bucks.

 

I purchased the valve and sensor (individually, not the assembly) not realizing that the sensor had a pre-formed, molded vacuum line attached. My dealer is telling me that the preformed vac line is not even available for purchase.

Any recommendation on how to remove the sensor from the premolded line to replace it? Should I cut the old one off and cut the vac line (rubber) off the end section of the premolded plastic line and connect it to the new sensor with a piece of new rubber line?

If that preformed plastic vac line ever goes bad, what do you do - especially if Ford doesn't offer a replacement part?

Thanks.

 

Have you tried speaking to a Mazda dealer?

 

I haven't, assumed Ford/Mazda would carry the same parts. I can check.

The thing is, I think that vac line is fine, I just need to change the sensor that attaches to it and don't know how to replace it since its connected to the premolded part of that vac line. I may try to cut and splice in the new sensor with a new peice of vac connecting the sensor to the premolded vac line.

Thanks.