AC pressure switch
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AC pressure switch Well it's getting hot and I want A/C...or want to try and get it to work.
Things I have done in order:
-Added Freon by jumping compressor relay B1 to B4 to allow system to pull in Freon.
-Pressure is about 35 psi on a 70-70* day. All is going well.
-AC will blow "colder" (lol) when compressor is jumped YAY but will not keep itself on BOOO
-I unhooked battery to maybe clear ant DTC's. Didn't work.
-I then hooked up DataMaster to read the AC pressure from the PCM...-13 psi hmmmm
_ I then cleared any engine DTC's via DataMaster but code came back within 10 seconds.
Here are the screen shots from logging.
Here you can see I am not "requesting" the AC to be on...in other words I didn't turn the HVAC **** to AC. Also It shows a DTC error of 66 which points to the pressure switch.
Now I turn the AC to "ON" and the green "0" is now a yellow "1" but I still show -13 psi...
SO, it seems the pressure sensor is bad ASSUMING the pressure reading I see in DataMaster is indeed the sensor on the High Pressure line. Correct?
Next issue...does anyone know if I can remove the sensor WITHOUT evacuating the system??I'm hoping there is some kind of valve that closes in order to replace the sensor.
Or is there a way I can pull a voltage from the sensor wires with a ohm meter to confirm it is indeed the sensor? What SHOULD the voltage be of the sensor?
Thanks guys!
Things I have done in order:
-Added Freon by jumping compressor relay B1 to B4 to allow system to pull in Freon.
-Pressure is about 35 psi on a 70-70* day. All is going well.
-AC will blow "colder" (lol) when compressor is jumped YAY but will not keep itself on BOOO
-I unhooked battery to maybe clear ant DTC's. Didn't work.
-I then hooked up DataMaster to read the AC pressure from the PCM...-13 psi hmmmm
_ I then cleared any engine DTC's via DataMaster but code came back within 10 seconds.
Here are the screen shots from logging.
Here you can see I am not "requesting" the AC to be on...in other words I didn't turn the HVAC **** to AC. Also It shows a DTC error of 66 which points to the pressure switch.
Now I turn the AC to "ON" and the green "0" is now a yellow "1" but I still show -13 psi...
SO, it seems the pressure sensor is bad ASSUMING the pressure reading I see in DataMaster is indeed the sensor on the High Pressure line. Correct?
Next issue...does anyone know if I can remove the sensor WITHOUT evacuating the system??I'm hoping there is some kind of valve that closes in order to replace the sensor.
Or is there a way I can pull a voltage from the sensor wires with a ohm meter to confirm it is indeed the sensor? What SHOULD the voltage be of the sensor?
Thanks guys!
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Replace it, its cooked....there should be a shrader valve behind it. BEE sure to wear safety glasses and have the new sensor ready to screw on quickly if the shrader valve is missing. The sensor is a variable resistor type. Also you should check the shrader valve is properly tightened before screwing on the sensor.
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Score! Thanks for the heads up!
Is there a special tool for the shrader valve tightening? Is it like a valve stem where there is a nifty tool for removing them?
I'll swing by AZ today and get a sensor.
Is there a special tool for the shrader valve tightening? Is it like a valve stem where there is a nifty tool for removing them?
I'll swing by AZ today and get a sensor.
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Just a standard tire valve tool is fine. Also check your wiring for a short in that circuit, probably ok but its quick to check. I'm not talking short to ground but across the circuit itself like 2 of the wires frayed together. Doubtful but possible.
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Well I replaced the sensor, unhooked the battery, logged data again and same DTC #66 again. Stopped the car stopped logging and cleared DTC. Took AC relay out, tried again turning AC on but then jumped the relay and I got DTC 66 and now 68 (which is shorted relay code lol).
So seems the PCM is reading the data correctly at the fuse box/relay for it to tell me it was shorted...but it is possibly not reading the data from the sensor right?
I know power goes to the compressor because I can jump it. It seems to be narrowing down between the sensor and PCM?
So seems the PCM is reading the data correctly at the fuse box/relay for it to tell me it was shorted...but it is possibly not reading the data from the sensor right?
I know power goes to the compressor because I can jump it. It seems to be narrowing down between the sensor and PCM?
Last edited by smitty2919; May 13, 2014 at 05:06 PM.
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Try pulling the connector off at the PCM and see if there is corrosion on any of the pins or sockets. Carefully check the wiring to the sensor . Hmmm I don't have a wiring diagram in frt of me and I can't remember what side the sensor is in. If its in the low side its possible the orifice tube is blocked causing a low pressure condition. From reading above I don't think so.... possible the shrader is effed up not letting the sensor see pressure readings? Might want to pull the sensor back off and test that too.
Last edited by RockinWs6; May 13, 2014 at 05:17 PM.
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I just pulled the sensor and used a shrader valve tool to unscrew it and when I heard it evacuating I tightened it again. I also used a rag and screw driver to push the shrader valve to make it work and it evacuated. No corrosion on the harness going into PCM or on PCM plugs either. Wire is tight inside harness plug at PCM
I'm following this:
Manual says -8psi = .12V and 448psi = 4.86V
When I jump "B" and "C" on the harness @ the sensor following the manual I get 452.5psi on DataMaster which should equate to about 4.9V
Setting up a proportion:
(4.86V*452.5psi)/448psi = 4.9V
Which, by the manual, would toward a faulty connection or bad sensor (which i hope not since it's new).
AAAND since I can see the 452.5psi reading in DataMaster when I jump the connector...Then that rules out a faulty connection at the PCM. Which would narrow down to the connection between the connector and sensor itself??
I would test the sensor to rule it out but I don't know the resistance through it with 0 psi applied to it.
I'm following this:
Manual says -8psi = .12V and 448psi = 4.86V
When I jump "B" and "C" on the harness @ the sensor following the manual I get 452.5psi on DataMaster which should equate to about 4.9V
Setting up a proportion:
(4.86V*452.5psi)/448psi = 4.9V
Which, by the manual, would toward a faulty connection or bad sensor (which i hope not since it's new).
AAAND since I can see the 452.5psi reading in DataMaster when I jump the connector...Then that rules out a faulty connection at the PCM. Which would narrow down to the connection between the connector and sensor itself??
I would test the sensor to rule it out but I don't know the resistance through it with 0 psi applied to it.
Last edited by smitty2919; May 13, 2014 at 07:25 PM.
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DAMN! I LOVE WHEN I'M RIGHT!
Ended up being that the connector terminals going onto the sensor were spread open too far and would not make contact with the sensor male terminals...
Took each wire out of the connector, used a pic to close the terminals back up and put connector back together. Plugged it back in, started the car and VOILA!
Thankfully it was something simple and stupid but that was $40 for a sensor I may not have needed to spend LOL.
Ended up being that the connector terminals going onto the sensor were spread open too far and would not make contact with the sensor male terminals...
Took each wire out of the connector, used a pic to close the terminals back up and put connector back together. Plugged it back in, started the car and VOILA!
Thankfully it was something simple and stupid but that was $40 for a sensor I may not have needed to spend LOL.
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I figured it was the sensor or a connection. I had trouble with mine at the PCM. I pulled the connectors off and sprayed everything with WD40. I was having all kinds of odd trouble. These sensors are known to be trouble though.
