Help with a P1445 CEL?

[Blossomforth]

hello

long time browser, first time poster. Anyway, im looking for some help regarding a check engine light on my truck. Its a '96 2.3L with a manual transmission. A couple months ago, my CEL came on and i retrieved a P1443 error code, which i fixed by replacing the purge solenoid. A month later, the CEL came back on, and this time its a P1445 error code, which means "purge flow sensor circuit high". I replaced the sensor, and it didnt help. I did some basic troubleshooting to see if any of the wires were faulty, and i came up empty. Next i replaced the ground wire and reground if on the body, and nothing changed. After that, i tried replacing the ecu wire on the harness, hoping that it wasnt getting a good signal, still nothing. Finally i replaced the sensonr incase i bought a bad one, and the truck has gone through a couple cycles with no change to the CEL. All thats left is to try rewiring the sensors power wire so it draws from somewhere else....otherwise i had no idea where to go next.

Where should i go from here? thanks for any help you guys can offer me!

 

[NIPs]

Recheck ur wires and make sure ur getting the right voltage to and from, check resistance in the wires, check related fuses and relays, and check vacuum lines as well

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[NIPs]

Is that saying I high voltage or high resistance

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[NIPs]

If its high resistance than more than likely its a bad connector, if its high voltage then its probably the sensor a sensor wire

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[Blossomforth]

Im not sure if its resistance or voltage. The PCM signal wire (Pin #11) is new, and i rewired the sensor's ground to the body, after removing the paint of course. I replaced the wires by removing the pin from the connectors, then used a small file to remove the crimped part on the pin and re soldered a new wire in its place. I tried to avoid splicing into the stock harness or doing any hackjob repairs.

I purchased another sensor the other day and nothing has changed. I even went as far as removing the pins from the connector and directly connecting it to the sensor to see if the plastic connector was preventing the pins from seating correctly, and nothing has changed. Im also not sure if the sensor is part of a circuit that has a fuse/relay on it, since everything else on the truck seems to work fine. I figured that a bad fuse or relay might trigger something else to act up as well.

Im not sure where to go from here, besides seeking professional help. I considered rewiring the sensors power source but im not sure if its a good idea to connect it directly to the battery with a inline fuse. At least it might eliminate another possible reason as to why im getting the code. Some fourm threads have mentioned that the code is trigger when the PCM can't "see" the sensor, but i've eliminated pretty much anything that could be preventing that condition.

im truly stumped.

 

[NIPs]

Some components use a fuse or relay, ur fuel pump for instance uses both a relay and a fuse, and only the fuel pump uses that fuse and that relay, go online or owners Manuel and look up the fuse box and battery junction box, that'll give u a map to start

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[Blossomforth]

I found a diagram of the power distribution block under the hood, and theres a couple PCM related fuses, and one relay. One particular fuse protects the circuit that includes the o2 sensors, egr, etc.

If the issue was on that circuit, would it give me additional engine codes? im only getting the P1445 code, so i figured i might get an o2 sensor code if the fuse was blown. Im going to check the fuse in the morning, so maybe its something small like that.

 

[NIPs]

Um it might give additional hard codes, but I would look for soft codes

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[HAPPY+RANGER+GUY]

Some forum threads have mentioned that the code is triggered when the PCM can't "see" the sensor, but i've eliminated pretty much anything that could be preventing that condition.

Keep in mind the PCM could be bad. Unfortunately this code can be quite persistent and some folks have resolved to living with it. Let us know if you do in fact solve this one...it will help out many others.

 

[Blossomforth]

Fixing the issue is my only option with this truck. I'm almost due to re-register it, and in Connecticut, it wont pass emissions if the CEL is lit.

heres what i've done up to this point, in detail:

1. Replaced the sensor twice, thinking i bought a bad sensor. Purchased them from Advanced Auto, BWD brand sensors. no change

2. Replaced all the rubber hosing between the throttle body and the evap canister. Purchased a roll of hose from Summit since i couldnt find the correct size locally. Cut the hoses to match the length of the stock hoses and used zip ties to securely attach them to the nipples on the sensor and solenoid. no change, but it helped clear up a previous P1443 code. When i was fixin the 1443 code, i had replaced the Solenoid and hoses, which cleared it up, and set off the new 1445 code.

3. Created a new sensor ground by splicing into the factory ground wire and attaching it to a paint free section of metal on the front support with a self tapping screw, again no change

4. Rewired the ecu feed wire (pin #11 from the sensor) by soldering new wire to the pins on the sensor and ecu, then reinstall it. no change

I dont think its a power issue since the code is a high voltage condition at the ecu, as in the ecu detects a voltage reading thats higher then spec. The only thing i can think of is that the connector between the harness and sensor isnt getting a solid connection and maybe its giving the ecu inconsistent volts?

All thats left would be trying a Ford brand sensor, replacing the connector itself, hard wiring the power source to the sensor with a inline fuse, or taking it to a professional and having them sort it out.

The truck drives ok, besides the issue. I've noticed a few other small things that may narrow down my problem:

- i only get around 90 miles of mixed driving from $20.00 worth of gas (about 5.25 gallons), which is below what most 2.3L owners get. That averages out to 16/17mpg or so. Already did a full tune up on the truck last winter, so its not fuel filter/air filter/plugs/wires/etc.

- on a rare occasion, the rpms spike when coming to a stop. normally it settles into an idle pretty quickly, but once in awhile it will stay around 1000-1500rpms over idle for a couple seconds before it settles down. my friend told me that manuals tend to do that on occasion, and this is my first one, so i tend to believe him. I also noticed that the idle control valve is on the same power grid as the purge sensor. something to consider.

- very occasional misfire condition, but the code doesnt stay in the pcm very long.
- Sometimes the truck shakes a bit, or vibrates more then usual at idle.

Phew, sorry this reply is so long. I like to be as detailed as possible so people with more experence can assist in helping find the potential problem. Thanks again for any help you guys can give me!

**EDIT**

So i found this website with a small test you can do to see if your sensor is working correctly (bottom of page)(http://www.tomshints.com/FordRanger/FR_EPS.htm) and mine was close to the recorded results in the test, so my sensor is working correctly and reading accurately.

This test gave me an idea, so i tried piercing the red power wire at the sensor to see what kind of reading i was getting, and its returning 14.60v consistently. Seems high.

 

[Bro/Dude]

same issue

Blossomforth,

It's odd, the first search I conducted on TRS lead me to you strigner. My 96' Ranger has exactly the same condition to the T. The symptoms you describe, the troubleshooting work etc....all the same!!

I have also replaced the sensor twice, done wire troubleshooting, added new hose/clamps, with the original efforts to remove the P1443 code (which is now gone).

P1445 is a bitch, I also needed to pass DEQ in Oregon, I found a work-around where a different address could be used instead of mailing address eliminating the need for DEQ (shady I know).

Anyway I also feel there is something else related to the system thats coupled to the P1445 hard code. The increased idle at times, the lower fuel economy, and the occasional miss fire are signs of ECR or P1443 problems even though the code doesn't hit. Im going to try another purge valve solenoid just incase the one I already put is is bad.

 

[Blossomforth]

yeah, its a bitch. I've done everything except replace the PCM and rewire the main power wire. I'm not good with electrical systems, so i tend to shy away from such repairs.

The issue has to be with the power wire though, since the PCM is detecting too much voltage and setting off the light. I had an idea to bypass the sensors factory power wire and build a test wire to see if my theory is correct, an to possibly rule out the possibility of a short in the power wire. I'll share my theory incase you want to try it before me, but dont take my word for it, as im not a automotive electrician and wiring is my weakness

1. shopping list: buy a used purge flow sensor pigtail from the local parts yard, roll of wire, heatstrinking, inline fuse for automotive applications, and a ring terminal that will go over the bolt on your positive battery cable. You could use your stock sensor power wire, but i rather spend a few bucks and not cut the factory wiring if i dont need to.

2. Remove the power pin from the pigtail connector and solder/crimp the inline fuse harness to it. Next, solder/crimp the other side of the fuse wire to the ring terminal. Youre basically hardwiring the sensor to the battery with a fuse in the middle to protect it.

3. Connect the pin to the purge flow connector (and into the sensor) then connect the ring terminal to the battery and run the truck. You gotta start the truck twice for the light to come on, if it does. If the light stays off, then you have isolated the issue, and the power wire needs to be repaired (or leave the test wire on and say **** it). If not, then it might be the PCM.

Precautions: the fuse needs to be handle enough volts to supply the sensor with enough power without popping, but the fuse cant be rated too high and flow enough power to damage the sensor. my local parts store sells inline fuse holders that come with 30a fuses, so it should be enough. Hell, the PCM primary fuse is protected by a 30a maxi fuse. I would also take the time to solder all the connectors and heatstrink them for the sake of protection. we're dealing with electricity after all.

If you end up trying my theory, then repost your results. I would be curious to see how it works out and if it fixes the problem. Good luck!