1999 F150 PO443 Evaporative Emission. Need Help
#1
08-20-2003, 04:11 PM
1999 F150 PO443 Evaporative Emission. Need Help
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<p>Hello,<br>
<br>
I was wondering if anyone could help me out with my car. I just bought a used
1999 F150 5.4L 4X4 XLT. Ran a OBD tester on it and got. <br>
<br>
PO443 code.<br>
<br>
Evaporative Emission Control System Purge Control Valve Circuit Malfunction. <br>
<br>
Car runs fine. Any thoughts anybody.<br>
<br>
And help would be appreciated. </p>
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<head>
<meta name="GENERATOR" content="Microsoft FrontPage 5.0">
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<title>New Page 1</title>
</head>
<body>
<p>Hello,<br>
<br>
I was wondering if anyone could help me out with my car. I just bought a used
1999 F150 5.4L 4X4 XLT. Ran a OBD tester on it and got. <br>
<br>
PO443 code.<br>
<br>
Evaporative Emission Control System Purge Control Valve Circuit Malfunction. <br>
<br>
Car runs fine. Any thoughts anybody.<br>
<br>
And help would be appreciated. </p>
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#2
08-20-2003, 07:31 PM
1999 F150 PO443 Evaporative Emission. Need Help
Hi and welcome to FTE 
The most common cause of a P0443 is a bad canister purge valve (near the brake booster on the firewall) but also check the vacuum hose to it to make sure it is intact and attached. The valve resistance should be 30-38 ohms across the 2 terminals.
The most common cause of a P0443 is a bad canister purge valve (near the brake booster on the firewall) but also check the vacuum hose to it to make sure it is intact and attached. The valve resistance should be 30-38 ohms across the 2 terminals.
#4
09-04-2003, 02:14 PM
1999 F150 PO443 Evaporative Emission. Need Help
Hi All,
I have the exact problem on my '96 F-150 with the 302cid. I replaced the valve and still have the problem. Is the P0403 code for an electrical malfunction or can it also detect system leaks? (The rear tank doesn't "hiss" when refilling like the front.) The light comes on immediately on the second start after clearing the MIL code so I wouldn't think it performed any kind of leak down test. A friend suggested that it may be the PCM iteself?!?!
I have the exact problem on my '96 F-150 with the 302cid. I replaced the valve and still have the problem. Is the P0403 code for an electrical malfunction or can it also detect system leaks? (The rear tank doesn't "hiss" when refilling like the front.) The light comes on immediately on the second start after clearing the MIL code so I wouldn't think it performed any kind of leak down test. A friend suggested that it may be the PCM iteself?!?!
#5
09-04-2003, 05:44 PM
1999 F150 PO443 Evaporative Emission. Need Help
Hi edek and welcome aboard
A P0443 means the PCM saw something it didnt like in the electrical part of the system. Was the code an on demand fault or in memory?
Possible causes:
VPWR circuit open.
EVAP CANISTER PURGE open.
EVAP CANISTER PURGE shorted to PWR GND or SIG RTN.
Damaged EVAP canister purge valve.
Damaged PCM.
A P0443 means the PCM saw something it didnt like in the electrical part of the system. Was the code an on demand fault or in memory?
Possible causes:
VPWR circuit open.
EVAP CANISTER PURGE open.
EVAP CANISTER PURGE shorted to PWR GND or SIG RTN.
Damaged EVAP canister purge valve.
Damaged PCM.
#6
09-04-2003, 08:21 PM
1999 F150 PO443 Evaporative Emission. Need Help
Hi racerguy,
Nice to be here.
I'm not sure of the difference between an on demand fault or in memory. If I'm not mistaken my code reader is giving me codes stored in memory.
I getting 12.5 V at the valve with ignition on so it doesn't seem to be an open circuit.
Nice to be here.
I'm not sure of the difference between an on demand fault or in memory. If I'm not mistaken my code reader is giving me codes stored in memory.
I getting 12.5 V at the valve with ignition on so it doesn't seem to be an open circuit.
#7
09-05-2003, 12:10 AM
1999 F150 PO443 Evaporative Emission. Need Help
An on demand code is something that is happening as you test it. A memory code is something the PCM saw recently but isnt neccessarily happening at the time you are testing it.
The pinpoint tests for the 2 are a bit different.
I'm not sure how most code readers work as I just use the Ford ones.
Will your's do an engine running test?
The pinpoint tests for the 2 are a bit different.
I'm not sure how most code readers work as I just use the Ford ones.
Will your's do an engine running test?
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#8
09-05-2003, 02:14 AM
1999 F150 PO443 Evaporative Emission. Need Help
The code must be a memory code as I can only read it after the PCM has set the Trouble Code bit on. My scanner will allow me to capture freeze frame data after the TC bit has been set but I don't know waht to look for that would be useful.
So far I have looked at:
1. Voltage at solenoid is 12.5 volts so not open
2. Infinite resistance between leads (so no short to common grnd?)
Next step is to disconnect wiring harness at PCM and check for shorts in the Grn/Yel wire (control lead?)
PS your FYI stickys have been immensely helpful. thanks
So far I have looked at:
1. Voltage at solenoid is 12.5 volts so not open
2. Infinite resistance between leads (so no short to common grnd?)
Next step is to disconnect wiring harness at PCM and check for shorts in the Grn/Yel wire (control lead?)
PS your FYI stickys have been immensely helpful. thanks
#9
09-05-2003, 08:18 AM
1999 F150 PO443 Evaporative Emission. Need Help
The pinpoint tests say that if the valve is good (resistance between 30-90 ohms) then to check the wiring from the valve to the PCM for shorts to ground, to each other, or opens. If that is good then it needs a PCM. I'm always a bit leery when when I get to needing a PCM. I always wonder if I missed something. The PCMs dont go bad all that often.
#10
09-18-2003, 11:00 AM
1999 F150 PO443 Evaporative Emission. Need Help
Looked more into the Evaporative Emission Control System Purge Control Valve Circuit Malfunction. Found out that the vacuum hose (one on bottom) was burnt from leaning against the engine. replace the tube with some other tube that I thought might work but code still pops up. Could it be the hose? Should I get a factor one or do I have more problems than that?
#11
09-19-2003, 02:49 PM
1999 F150 PO443 Evaporative Emission. Need Help
Hey guys, I got almost the same problem except the code is P1451, I think, but anyhow it gave the same message about the Evaporative Emissions. I checked all the hoses and they're fine. Should i just pull a canister purge valve off another F150 and replace mine it?
Thanks,
Chris
Thanks,
Chris
#12
09-21-2003, 11:27 PM
#13
09-21-2003, 11:32 PM
1999 F150 PO443 Evaporative Emission. Need Help
It's hard to find an F150 that isn't already stripped at the wrecking yard. I finally found one but the idiot wanted $45 for it. I can buy a brand new one from Autozone for $35.
Another question, does this problem cause my engine to run poorly or is it just an emissions thing that has nothing to do with truck performance?
Thanks,
Chris
Another question, does this problem cause my engine to run poorly or is it just an emissions thing that has nothing to do with truck performance?
Thanks,
Chris
#14
09-21-2003, 11:46 PM
#15
09-22-2003, 01:31 PM
1999 F150 PO443 Evaporative Emission. Need Help
Good to know, I don't really notice my truck running any different but if the check engine light is on I better fix the problem.
By the way, on the Canister Evaporative Valve it has a tag that says it's got to have 1PSI running in it. Do I have to worry about pressurizing the new one or will it create its own pressure once I install it.
Thanks,
Chris
By the way, on the Canister Evaporative Valve it has a tag that says it's got to have 1PSI running in it. Do I have to worry about pressurizing the new one or will it create its own pressure once I install it.
Thanks,
Chris