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AC compressor valve blew the refrigerant out.

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#24 ·
Zipzit said:
Mystery abbreviation TIPM?
Click to expand...
The TIPM is the Totally Integrated Power Module aka the fusebox next to the battery. It is the central brain that communicates with everything. Mine had a relay in the circuit board under the fuses that went bad that caused the over pressure on the AC. It's not user serviceable. If you can't get one at the dealer I've had luck with Mack's TIPM repair.
 
Discussion starter · #25 ·
Bob Sanders said:
If it went up to 400 before turning on, then I would suspect a faulty A|C pressure sensor
Click to expand...
I let it run then turned off. Pressure was equalizing but stoped at 75psi low and 150 high.

I waited a few minutes then started the car with the AC on and watched the pressure climb to 400 at which point the fan started working and the pressure went down to 200-250.

when we tested when we did the repair it did something similar but the fan started working at 350psi.

so I'm thinking it's the high pressure switch.
 
Discussion starter · #27 ·
Today we hooked up the car the the scan tool. We verified the high pressure switch is working properly.

we had both dials hooked up to the AC system and the scan tool. We could see the pressure reading is matching on both the scan tool and the dials.

so we don't think it is the pressure switch.

what we did notice is the fan has a delay in coming on once you see the command to turn it on in the scan tool.

so we are suspecting the fan could be bad and causing issues.
 
#28 ·
Zoti said:
Today we hooked up the car the the scan tool. We verified the high pressure switch is working properly.

we had both dials hooked up to the AC system and the scan tool. We could see the pressure reading is matching on both the scan tool and the dials.

so we don't think it is the pressure switch.

what we did notice is the fan has a delay in coming on once you see the command to turn it on in the scan tool.

so we are suspecting the fan could be bad and causing issues.
Click to expand...
How long of a delay?
 
Discussion starter · #29 · (Edited)
A few seconds.
The issue is, the pressure on the AC systems goes high. Above 400PSI. When then fan turns on, it lowers the temp.

will the fan run if the engine is off and the pressure is high?

someone mentioned the fan should turn on at 280psi. I saw that happening today. However, yesterday, after it blew the refrigerant again, I saw it open only at 400PSI.

this seem to happen when I drive the car, park it for a bit then start it up to drive again. When I start it up the pressure builds up and the fan is not turning on immediately.

also happened when I drove the car on a hot day, then parked it. After a few minutes the refrigerant blew out.
 
#30 ·
Zoti said:
someone mentioned the fan should turn on at 280psi. I saw that happening today. However, yesterday, after it blew the refrigerant again, I saw it open only at 400PSI.
Click to expand...
No. Manual says 240. It also says that the computer disengages the compressor clutch when pressure reaches 431psi
From the manual:
=================================
4 - Heating and Air Conditioning / Controls / TRANSDUCER, A/C Pressure / Operation
OPERATION
The A/C pressure transducer monitors the pressures in the high side of the refrigerant system through its connection to a fitting on the refrigerant line. The A/C pressure transducer will change its internal resistance in response to the pressures it monitors. A Schrader-type valve in the discharge line fitting permits the A/C pressure transducer to be removed or installed without disturbing the refrigerant in the A/C system.

The Powertrain Control Module (PCM) provides a 5 volt reference signal and a sensor ground to the A/C pressure transducer, and then monitors the output voltage of the transducer on a sensor return circuit to determine refrigerant pressure. The PCM is programmed to respond to the A/C pressure transducer and other sensor inputs by controlling the operation of the A/C clutch and the radiator cooling fan to help optimize A/C system performance and to protect A/C system components from damage. The PCM will disengage the A/C clutch when high side pressure rises above 2971 kPa (431 psi) or falls below 206 kPa (30 psi). The A/C pressure transducer input to the PCM also prevents the A/C clutch from engaging when ambient temperatures are below about 10° C (50° F), due to the pressure/temperature relationship of the refrigerant. When the refrigerant pressure rises above 1655 kPa (240 psi), the PCM will actuate the cooling fan.
=================================
 
Discussion starter · #31 ·
Bob Sanders said:
No. Manual says 240. It also says that the computer disengages the compressor clutch when pressure reaches 431psi
From the manual:
=================================
4 - Heating and Air Conditioning / Controls / TRANSDUCER, A/C Pressure / Operation
OPERATION
The A/C pressure transducer monitors the pressures in the high side of the refrigerant system through its connection to a fitting on the refrigerant line. The A/C pressure transducer will change its internal resistance in response to the pressures it monitors. A Schrader-type valve in the discharge line fitting permits the A/C pressure transducer to be removed or installed without disturbing the refrigerant in the A/C system.

The Powertrain Control Module (PCM) provides a 5 volt reference signal and a sensor ground to the A/C pressure transducer, and then monitors the output voltage of the transducer on a sensor return circuit to determine refrigerant pressure. The PCM is programmed to respond to the A/C pressure transducer and other sensor inputs by controlling the operation of the A/C clutch and the radiator cooling fan to help optimize A/C system performance and to protect A/C system components from damage. The PCM will disengage the A/C clutch when high side pressure rises above 2971 kPa (431 psi) or falls below 206 kPa (30 psi). The A/C pressure transducer input to the PCM also prevents the A/C clutch from engaging when ambient temperatures are below about 10° C (50° F), due to the pressure/temperature relationship of the refrigerant. When the refrigerant pressure rises above 1655 kPa (240 psi), the PCM will actuate the cooling fan.
=================================
Click to expand...
Thanks. This is super useful. Where is this info from?

We had the car hooked up to gauges and also had a scanner watching live data. The A/C pressure data was matching the on the scanner and the gauges.

I think the radiator fan operation is delayed because I saw the pressure go up to 400psi before the fan turned on but that was right when I started the car after not was sitting off for a bit so there was already pressure in the AC system.

I have Jscan so I tested the radiator fan and I can command it to run at full speed with Jscan. I Don't think it is the fan itself.

I'm looking for ideas.
 
#32 ·
Zoti said:
Thanks. This is super useful. Where is this info from?
Click to expand...
From the official Mopar Tech Authority Manual.

The pressure on the ac will be high for HOURS after you run the ac then turn the car off (hot engine means hot refrigerant which means higher pressure). The slight delay in the fan at start up is normal. I am not sure why you are so concerned about this 400 number? The compressor is turned off at 430 psi and the relief valve doesn't blow until something like 500psi. Sooooo.... although 400 is a bit on the high scale, it is still within normal operating parameters.
 
Discussion starter · #33 ·
Bob Sanders said:
From the official Mopar Tech Authority Manual.

The pressure on the ac will be high for HOURS after you run the ac then turn the car off (hot engine means hot refrigerant which means higher pressure). The slight delay in the fan at start up is normal. I am not sure why you are so concerned about this 400 number? The compressor is turned off at 430 psi and the relief valve doesn't blow until something like 500psi. Sooooo.... although 400 is a bit on the high scale, it is still within normal operating parameters.
Click to expand...
I'm concerned because it blew the refrigerant out 3 times now. Once, a year ago. Then a week ago, then a few days after replacing the expansion valve and receiver dryer.

The system seem to run fine when we test it but will blow the refrigerant under those conditions. So I'm lost as to why. Do you have any suggestions where I should look next? Maybe it's just a faulty pressure relief valve?

Would the system set a code for over pressure in the AC system?
 
#34 ·
Zoti said:
I'm concerned because it blew the refrigerant out 3 times now. Once, a year ago. Then a week ago, then a few days after replacing the expansion valve and receiver dryer.

The system seem to run fine when we test it but will blow the refrigerant under those conditions. So I'm lost as to why. Do you have any suggestions where I should look next? Maybe it's just a faulty pressure relief valve?

Would the system set a code for over pressure in the AC system?
Click to expand...
But it's not possible to blow the relief if the computer is doing its job and cutting off the compressor at the safety cutoff of 430 psi and the relief doesn't blow until about 500 (unless of course the system is being over charged). Either the relief is blowing prematurely or the computer is not shutting down the compressor at the safety cutoff pressure.

The pressure relief valve spec from the manual:

A/C Compressor​
Zexel DKS-17DS - 2.8L Diesel Engine​
VC-46 PAG oil​
Visteon RS-18 - 3.0L/3.6L Engine​
Visteon RS-18 - 3.6L Engine with R-1234yf refrigerant​
ND-12 PAG oil only
A/C Clutch Air Gap​
0.30 - 0.60 mm (0.012 - 0.024 in.)​
2.8L Diesel Engine
0.35 - 0.65 mm (0.014 - 0.025 in.)​
3.0L/3.6L Engine
A/C Clutch Coil Draw​
3.3 amps Max @ 12V ± 0.5V @ 21° C (70° F)​
2.8L Diesel Engine
4.0 amps Max @ 12V ± 0.5V @ 21° C (70° F)​
3.0L/3.6L Engine
A/C Clutch Coil Resistance4.0 - 4.4 ohms @ 21° C (70° F)2.8L Diesel Engine
3.0 - 4.0 ohms @ 21° C (70° F)3.0L/3.6L Engine
Freeze-up Control​
Evaporator Temperature Sensor​
HVAC housing mounted - input to Powertrain Control Module (PCM)​
High PSI Control​
A/C Pressure Transducer​
Refrigerant line mounted - input to PCM - PCM disengages compressor clutch above 4.519 volts​
High Pressure Relief Valve​
A/C Compressor mounted - opens at a discharge pressure over 3430 - 3930 kPa (497 - 570 psi)​
Low PSI Control​
A/C Pressure Transducer​
Refrigerant line mounted - input to PCM - PCM disengages compressor clutch below 0.451 volts​
R-1234yf Refrigerant Charge Capacity(Refer to 04 - Vehicle Quick Reference/Capacities and Recommended Fluids/Specifications) Also see A/C Underhood Specification Label located in the engine compartment
R-134a Refrigerant Charge Capacity​
(Refer to 04 - Vehicle Quick Reference/Capacities and Recommended Fluids/Specifications) Also see A/C Underhood Specification Label located in the engine compartment
 
Discussion starter · #35 ·
Bob Sanders said:
But it's not possible to blow the relief if the computer is doing its job and cutting off the compressor at the safety cutoff of 430 psi and the relief doesn't blow until about 500 (unless of course the system is being over charged). Either the relief is blowing prematurely or the computer is not shutting down the compressor at the safety cutoff pressure.

The pressure relief valve spec from the manual:

​
A/C Compressor​
Zexel DKS-17DS - 2.8L Diesel Engine​
VC-46 PAG oil​
Visteon RS-18 - 3.0L/3.6L Engine​
Visteon RS-18 - 3.6L Engine with R-1234yf refrigerant​
ND-12 PAG oil only
A/C Clutch Air Gap​
0.30 - 0.60 mm (0.012 - 0.024 in.)​
2.8L Diesel Engine
0.35 - 0.65 mm (0.014 - 0.025 in.)​
3.0L/3.6L Engine
A/C Clutch Coil Draw​
3.3 amps Max @ 12V ± 0.5V @ 21° C (70° F)​
2.8L Diesel Engine
4.0 amps Max @ 12V ± 0.5V @ 21° C (70° F)​
3.0L/3.6L Engine
A/C Clutch Coil Resistance4.0 - 4.4 ohms @ 21° C (70° F)2.8L Diesel Engine
3.0 - 4.0 ohms @ 21° C (70° F)3.0L/3.6L Engine
Freeze-up Control​
Evaporator Temperature Sensor​
HVAC housing mounted - input to Powertrain Control Module (PCM)​
High PSI Control​
A/C Pressure Transducer​
Refrigerant line mounted - input to PCM - PCM disengages compressor clutch above 4.519 volts​
High Pressure Relief Valve​
A/C Compressor mounted - opens at a discharge pressure over 3430 - 3930 kPa (497 - 570 psi)​
Low PSI Control​
A/C Pressure Transducer​
Refrigerant line mounted - input to PCM - PCM disengages compressor clutch below 0.451 volts​
R-1234yf Refrigerant Charge Capacity(Refer to 04 - Vehicle Quick Reference/Capacities and Recommended Fluids/Specifications) Also see A/C Underhood Specification Label located in the engine compartment
R-134a Refrigerant Charge Capacity​
(Refer to 04 - Vehicle Quick Reference/Capacities and Recommended Fluids/Specifications) Also see A/C Underhood Specification Label located in the engine compartment
Click to expand...
Thats's exactly what I am trying to figure out. Your post helps me because before I was trying to guess what those pressures were.

I need to see if the clutch disengages or if it is the relief valve. any ideas on how to test?
 
#36 ·
Zoti said:
Thats's exactly what I am trying to figure out. Your post helps me because before I was trying to guess what those pressures were.

I need to see if the clutch disengages or if it is the relief valve. any ideas on how to test?
Click to expand...
My TOTAL GUESS would be to disconnect the fan and run it up until you hit 430 or 440.... (although you may get an error code) or you can just connect a pressure gauge to it, run it into the cab and keep an eye on it.
 
Discussion starter · #37 ·
Bob Sanders said:
My TOTAL GUESS would be to disconnect the fan and run it up until you hit 430 or 440.... (although you may get an error code) or you can just connect a pressure gauge to it, run it into the cab and keep an eye on it.
Click to expand...
So what I'm doing now is run JScan and watch the hi side pressure.

so far it is running normally.

I am also turning the AC off before turning the car off. Then when I start the car, I let it run a bit before turning the AC on while watching the pressure.

I'm hoping to catch it when it happens again so I can figure out what is going on.
 
Discussion starter · #38 ·
So i was reading some posts and websites about the wrangler radiator. I found a post that was taking about the radiator positive cable and fuseable link that connects directly to the battery positive post.

a lot of people said that it comes loose.

mine wasn't loose but I undid it and re tightened. I swear the fan is working faster now.
 
Discussion starter · #39 ·
so after further testing and not being able to find anything wrong with the HVAC system I decided to concentrate on the radiator cooling fan. I read some posts about the fan positive wire which is connected directly to the battery positive terminal, getting loose because the nut is getting loose and people getting errors because of that.

I checked mine and it was not loose but I opened and retightened all the nuts on the positive battery post and I swear the fan is working faster now. I can actually hear it.

Could it be that the PCM is sending a PWM to the fan but because the positive wire is loose the fan does not spin fast enough?
 
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