P0433 Fault Code
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Mountain Pass
Joined: May 2004
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P0433 Fault Code
I am at my wits end here, I get this code Evap Emission Control Purge C Fault. I changed the purge valve that is located on the firewall (next to the power booster), cleared the code drove for 20 miles the check engine light came back on, bought a new gas cap, at the recomendation of the dealer parts dept., cleared the code and back on again. I bought a new charcoal canister (just the canister) cleared the code and back on it came, then I bought the charcoal canister purge valve, the valve actually located on the canister, cleared the code, drove 150 miles and back on. I checked for blockages in the lines. I changed the rubber hose that goes from the intake to the purge valve and also from the charcoal canister to the gas tank. We'll see if that does it but I have done everything short of actually having the smoke test done. Does anybody have any other suggestions as to what the cause of the P0433 fault code could be?? Thanks in advance for any additional help. Thank you.
Hotshot
Joined: Jan 2004
Posts: 19,762
Likes: 1,079
From: St Louis
There is no valid fault code of P0433 for any Ford from 96-03. Your profile says you have a 97. You're either working on a different vehicle, have a faulty code read, or mistyped the fault code in your post.
Either way, you've been spinning your wheels hanging parts on the vehicle without following the proper diagnostic procedure.
I suspect you actually have a P0443 code which indicates an electical fault in the purge valve circuit.
Here is the diagnostic procedure from the service manual:
That should get it diagnosed correctly
Steve
Either way, you've been spinning your wheels hanging parts on the vehicle without following the proper diagnostic procedure.
I suspect you actually have a P0443 code which indicates an electical fault in the purge valve circuit.
Here is the diagnostic procedure from the service manual:
HX11 DTC P0443: CHECK VPWR VOLTAGE TO EVAP CANISTER PURGE VALVE
Diagnostic Trouble Code (DTC) P0443 indicates a failure in the EVAP canister purge valve circuit.
Possible causes:
-- VPWR circuit open.
-- EVAP canister purge valve circuit open.
-- EVAP canister purge valve circuit shorted to PWR GND.
-- EVAP canister purge valve circuit shorted to VPWR.
-- Damaged EVAP canister purge valve.
-- Damaged PCM.
l Key off.
l Disconnect EVAP canister purge valve.
l Key on, engine off.
l Measure voltage between VPWR circuit at the EVAP canister purge valve harness connector and battery negative post. (red wire at connector - steve)
l Key off.
l Was voltage greater than 10.5 volts?
Yes
GO to «HX12».
No
REPAIR open circuit. RESTORE vehicle. COMPLETE PCM Reset to clear DTCs. RERUN «Quick Test».
HX12 CHECK EVAP CANISTER PURGE VALVE RESISTANCE
NOTE:
EVAP canister purge valve resistance reading must be taken with engine cooled down.
l Disconnect EVAP canister purge valve.
l Measure EVAP canister purge valve (EVAP canister purge valve) resistance.
l Is resistance between 30 and 38 ohms?
Yes
GO to «HX13».
No
REPLACE damaged EVAP canister purge valve. COMPLETE PCM Reset to clear DTCs. RERUN EVAP System Leak Test at evaporative test port to VERIFY the repair. RERUN Evaporative Emission Running Loss Monitor Repair Verification Drive Cycle (refer to «Section 2A», Drive Cycles).
HX13 CHECK EVAP CANISTER PURGE VALVE CIRCUIT FOR OPEN IN HARNESS
l Install breakout box, leave PCM disconnected.
l Measure resistance of EVAP canister purge valve circuit between PCM test pin 56 and EVAP canister purge valve harness connector.
l Is resistance less than 5.0 ohms?
Yes
GO to «HX14».
No
REPAIR open circuit. RESTORE vehicle. COMPLETE PCM Reset to clear DTCs. RERUN «Quick Test».
HX14 CHECK EVAP CANISTER PURGE VALVE CIRCUIT FOR SHORT TO PWR GND IN HARNESS
l Disconnect scan tool from DLC.
l Measure resistance between PCM test pin 56 and PCM test pins 24 and 103.
l Are both resistances greater than 10,000 ohms?
Yes
GO to «HX15».
No
REPAIR short circuit. RESTORE vehicle. COMPLETE PCM Reset to clear DTCs. RERUN «Quick Test».
HX15 CHECK EVAP CANISTER PURGE VALVE CIRCUIT FOR SHORT TO VPWR IN HARNESS
l Key on, engine off.
l Measure voltage between PCM test pin 56 and PCM test pins 51 and 103.
l Key off.
l Was voltage greater than 10.5 volts?
Yes
REPAIR short circuit. RESTORE vehicle. COMPLETE PCM Reset to clear DTCs. RERUN «Quick Test».
No
REPLACE damaged PCM. RESTORE vehicle. RERUN «Quick Test».
Diagnostic Trouble Code (DTC) P0443 indicates a failure in the EVAP canister purge valve circuit.
Possible causes:
-- VPWR circuit open.
-- EVAP canister purge valve circuit open.
-- EVAP canister purge valve circuit shorted to PWR GND.
-- EVAP canister purge valve circuit shorted to VPWR.
-- Damaged EVAP canister purge valve.
-- Damaged PCM.
l Key off.
l Disconnect EVAP canister purge valve.
l Key on, engine off.
l Measure voltage between VPWR circuit at the EVAP canister purge valve harness connector and battery negative post. (red wire at connector - steve)
l Key off.
l Was voltage greater than 10.5 volts?
Yes
GO to «HX12».
No
REPAIR open circuit. RESTORE vehicle. COMPLETE PCM Reset to clear DTCs. RERUN «Quick Test».
HX12 CHECK EVAP CANISTER PURGE VALVE RESISTANCE
NOTE:
EVAP canister purge valve resistance reading must be taken with engine cooled down.
l Disconnect EVAP canister purge valve.
l Measure EVAP canister purge valve (EVAP canister purge valve) resistance.
l Is resistance between 30 and 38 ohms?
Yes
GO to «HX13».
No
REPLACE damaged EVAP canister purge valve. COMPLETE PCM Reset to clear DTCs. RERUN EVAP System Leak Test at evaporative test port to VERIFY the repair. RERUN Evaporative Emission Running Loss Monitor Repair Verification Drive Cycle (refer to «Section 2A», Drive Cycles).
HX13 CHECK EVAP CANISTER PURGE VALVE CIRCUIT FOR OPEN IN HARNESS
l Install breakout box, leave PCM disconnected.
l Measure resistance of EVAP canister purge valve circuit between PCM test pin 56 and EVAP canister purge valve harness connector.
l Is resistance less than 5.0 ohms?
Yes
GO to «HX14».
No
REPAIR open circuit. RESTORE vehicle. COMPLETE PCM Reset to clear DTCs. RERUN «Quick Test».
HX14 CHECK EVAP CANISTER PURGE VALVE CIRCUIT FOR SHORT TO PWR GND IN HARNESS
l Disconnect scan tool from DLC.
l Measure resistance between PCM test pin 56 and PCM test pins 24 and 103.
l Are both resistances greater than 10,000 ohms?
Yes
GO to «HX15».
No
REPAIR short circuit. RESTORE vehicle. COMPLETE PCM Reset to clear DTCs. RERUN «Quick Test».
HX15 CHECK EVAP CANISTER PURGE VALVE CIRCUIT FOR SHORT TO VPWR IN HARNESS
l Key on, engine off.
l Measure voltage between PCM test pin 56 and PCM test pins 51 and 103.
l Key off.
l Was voltage greater than 10.5 volts?
Yes
REPAIR short circuit. RESTORE vehicle. COMPLETE PCM Reset to clear DTCs. RERUN «Quick Test».
No
REPLACE damaged PCM. RESTORE vehicle. RERUN «Quick Test».
Steve
Last edited by projectSHO89; Apr 4, 2007 at 09:18 AM.
Thread Starter
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Mountain Pass
Joined: May 2004
Posts: 226
Likes: 2
I did type the code in wrong it is a P0443, sorry about that. I'll follow the guide below and get it fixed. Thanks for all the advise and for the correct way to get it fixed, much appreciated!!!
Hotshot
Joined: Jan 2004
Posts: 19,762
Likes: 1,079
From: St Louis
There's also a pretty good thread that I dug up earlier from a couple of years ago in which one of the moderators went through this one with a board member.
I didn't bookmark it, however, you should be able to easily find it by SEARCHing for "P0443"
Steve
I didn't bookmark it, however, you should be able to easily find it by SEARCHing for "P0443"
Steve
Thread Starter
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Mountain Pass
Joined: May 2004
Posts: 226
Likes: 2
I have a few questions, probably stupid to ask, what is a breakout box and what does PCM stand for, and the last one is where can I find the PCM test pin 56. Thanks again for all your help and advise.
Hotshot
Joined: Jan 2004
Posts: 19,762
Likes: 1,079
From: St Louis
A breakout box (BOB) is a special piece of test equipment for accessing specific pins of a harness or connector "in-circuit". You will have to do without it...
PCM=Powertrain Control Module - the brains of the vehicle aka the ecomputer.
For the resistance checks that are specified using the BOB, you'll just have to use your meter probe directly in the connector at the correct pin (56) of the PCM harness connector. FWIW, PCM pin 56 connects to the low side of the CP valve connector. It needs to be checked for continuity and to ensure that there is no short to ground, vehicle power, or another circuit.
Steve
PCM=Powertrain Control Module - the brains of the vehicle aka the ecomputer.
For the resistance checks that are specified using the BOB, you'll just have to use your meter probe directly in the connector at the correct pin (56) of the PCM harness connector. FWIW, PCM pin 56 connects to the low side of the CP valve connector. It needs to be checked for continuity and to ensure that there is no short to ground, vehicle power, or another circuit.
Steve
New User
Joined: May 2006
Posts: 9
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Any Ideas?
Hi,
I have a 1996 F150 4.9L straight 6. I just replaced my PCM after running through the diagnostic procedure in my Ford Service manual the O2 sensor heater circuit malfunction codes. Well, after replacing the PCM I didn't have any more problems with the O2 heaters, but now this P0443 code shows up. I just ran through the diagnostic procedure in the Ford manual, and reached the step that says "Replace PCM". I just replaced it yesterday... Is it possible something could be causing the PCM to go bad... if so... Any ideas?
I have a 1996 F150 4.9L straight 6. I just replaced my PCM after running through the diagnostic procedure in my Ford Service manual the O2 sensor heater circuit malfunction codes. Well, after replacing the PCM I didn't have any more problems with the O2 heaters, but now this P0443 code shows up. I just ran through the diagnostic procedure in the Ford manual, and reached the step that says "Replace PCM". I just replaced it yesterday... Is it possible something could be causing the PCM to go bad... if so... Any ideas?
Last edited by bigcountry350; Jun 3, 2007 at 08:29 PM.
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New User
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p0443
Would like to know if replacing the lines worked for you. I replace the pcm, purge valve. I Still have a code of p0443
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I also have a 1997 ford ranger....yesterday i took it to get the E check done...but they immediately told me that it will not pass... apparently my check engine light WILL NOT COME ON not that it wont go off it wont go on..ever point blank, like when you stick the key in the ignition its supposed to come on until you start the truck up, they went ahead and checked the computers and i got a code of p0443...same thing....i just bought this truck used from a private dealer....and im thinking the previous owner saw that he light wont go off, then unplugged it so i wont realize and sold it to me...anyway a neighbor of mine who is pretty mechanical savvy said he will take a look and take me to get a new part and put it on...if needed. but what i was wondering is where do you look to find this evap thing IN THE TRUCK? im an 18 year old girl...this is my first vehicle..and i know nothing...any comments on what you think will be helpful! thanks so much
~Amanda
~Amanda
Fleet Owner
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From: 0,0,1
Most times a code P0443 means the gas cap isn't sealing and is allowing air to leak past it. If it only happens occasionally it might mean you're not tightening the gas cap 3 clicks. If you are tightening the gas cap enough, then it could mean you need a new gas cap.
Hotshot
Joined: Jan 2004
Posts: 19,762
Likes: 1,079
From: St Louis
P0443 is an electrical circuit fault and cannot be triggered by an unsealed fuel cap. See the excerpt from the service manual posted above.
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