pressure transducer
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pressure transducer
Hello,
I've got a situation with my AC that i can't resolve. AC works intemittently. Sometime it will run without fail for more than week. It worked noon today but right now the clutch won't engage. I've checked low and high pressure with a gauge everything looks normal. Right now I suspect the pressure transducer.
When the system is running i've only seen voltage out between 1.0 and 2.25. I've not seen a voltage come out of it higher than about 2.25. The clutch will engage if it sends voltage above 1.2 and it seems to hold steady when about 2, but sometime it will float about 1.5 then rapidly drop below 1.0. When it does this you can see the clutch disengage as the voltage out drops below about 1.2. I was sure the transducer was the problem until this evening. It won't come on but the voltage out reads about 1.3.
I understand that the operating range is .5v to 4.5v for the transducer output, but what is the nominal operating behavior? Shouldnt the clutch engage for anything above .5? To be sure, i've had the pressure checked by a local garage. They see what i see, pressure normal.
Any ideas. Thanks.
2005 Dakota 4.7
I've got a situation with my AC that i can't resolve. AC works intemittently. Sometime it will run without fail for more than week. It worked noon today but right now the clutch won't engage. I've checked low and high pressure with a gauge everything looks normal. Right now I suspect the pressure transducer.
When the system is running i've only seen voltage out between 1.0 and 2.25. I've not seen a voltage come out of it higher than about 2.25. The clutch will engage if it sends voltage above 1.2 and it seems to hold steady when about 2, but sometime it will float about 1.5 then rapidly drop below 1.0. When it does this you can see the clutch disengage as the voltage out drops below about 1.2. I was sure the transducer was the problem until this evening. It won't come on but the voltage out reads about 1.3.
I understand that the operating range is .5v to 4.5v for the transducer output, but what is the nominal operating behavior? Shouldnt the clutch engage for anything above .5? To be sure, i've had the pressure checked by a local garage. They see what i see, pressure normal.
Any ideas. Thanks.
2005 Dakota 4.7
Site Moderator-Dodge Tech
Joined: Sep 2010
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From: Nashville, Tennessee
We almost never look at the transducer voltage solely. What you're seeing may not be what it actually is because it's fluctuating. There is a delay where the PCM reacts. The high pressure is in the scan tool data. Basic check to see if transducer matches what the high side gauge reads.
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Registered User
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Had a diag done at the dealer today fofr several reasons, pressure transducer was confirmed bad. Not surprised I suppose. When vehicle was off for 12 hours and gauges were normal but voltage was below 1v that just didnt make sense. Has anyone changed this? I presume you can remove it by hand. Any caveats that I should be aware of?