"Check Air Conditioning"

[jjdynomite75]

2005 LC 180,000 Miles

Preface. I've searched this problem on Mud many times. To no avail. I'm hoping I have a unique fix that I'm not considering.

Firstly, I've recently had a mechanic replace my Timing Belt, Water Pump, Fan Clutch, A/C compressor, A/C Pressure sensor and Under Hood relay box. The last two were in response to the A/C not blowing cold. Here's the crazy part. The A/C blows cold when the engine is at or above 1050 RPMs. All day. Whether it is moving or not. Sitting in the driveway, revving it above 1050, blows cold. Driving down the road with no stops, blows cold. The moment i let off the gas, the A/C light on the nav screen blinks, the compressor shuts off and it blows warm air and the screen says "Check Air Conditioning"

As soon as i start moving again, I can hit the A/C button on the nav screen and it'll start blowing cold immediately again.

I covet any wisdom. Thanks

 

[Zjohnsonua]

2005 LC 180,000 Miles

Preface. I've searched this problem on Mud many times. To no avail. I'm hoping I have a unique fix that I'm not considering.

Firstly, I've recently had a mechanic replace my Timing Belt, Water Pump, Fan Clutch, A/C compressor, A/C Pressure sensor and Under Hood relay box. The last two were in response to the A/C not blowing cold. Here's the crazy part. The A/C blows cold when the engine is at or above 1050 RPMs. All day. Whether the car is moving or not. Sitting in the driveway, revving it above 1050, blows cold. Driving down the road with no stops, blows cold. The moment i let off the gas, the A/C light on the nav screen blinks, the compressor shuts off and it blows warm air and the screen says "Check Air Conditioning"

As soon as i start moving again, I can hit the A/C button on the nav screen and it'll start blowing cold immediately again.

I covet any wisdom. Thanks

likely undercharged. need pressure gage read outs to confirm.

 

[katit]

likely undercharged. need pressure gage read outs to confirm.

Yepp.. Sounds like it. More RPM, more pressure. Sensor allows AC compressor clutch on. When idle pressure goes down and computer shuts down compressor.

Need to confirm with gauges.

 

[jjdynomite75]

Yepp.. Sounds like it. More RPM, more pressure. Sensor allows AC compressor clutch on. When idle pressure goes down and computer shuts down compressor.

Need to confirm with gauges.

Thank you for your response. Just confirmed with the mechanic that the pressures were good. Any other ideas?

 

[SteveH]

Could the A/C clutch be slipping or have too large a gap to engage fully? You might check the RPM of the A/C pulley vs. another similar pulley. Could the A/C clutch be losing voltage at lower engine speeds? You could put a VOM on the clutch wires and measure the voltage and idle and higher RPMs.

 

[jjdynomite75]

Could the A/C clutch be slipping or have too large a gap to engage fully? You might check the RPM of the A/C pulley vs. another similar pulley. Could the A/C clutch be losing voltage at lower engine speeds? You could put a VOM on the clutch wires and measure the voltage and idle and higher RPMs.

I'm beginning to wonder if the compressor that was installed was faulty. Maybe I should warranty it and get a new one.

 

[jjdynomite75]

I'm beginning to wonder if the compressor that was installed was faulty. Maybe I should warranty it and get a new one.

Still having this problem. New A/C compressor (clutch engages and blows cold) but only at 1100 rpm. once it goes below 1100 the compressor cuts off) fan blows, new pressure sensor, pressures are good. Any other ideas of what this could be? Thanks for your input.

 

[jjdynomite75]

Update on my A/C Problem.

Recap:

New Timing Belt, Water Pump, Fan Clutch, A/C compressor, A/C Pressure sensor and Under Hood relay box (part of my A/C problem troubleshooting). A/C blows cold only when the RPM's are 1100 or above. Compressor shuts off at idle. A/C button blinks and screen says Check Air Conditioning

Pressure reading at 1600 RPM's below. Could my problem be A/C amplifier? Any other ideas? Thanks

 

[Zjohnsonua]

Whats your ambient temp?

Knee jerk says undercharged due to low press on lo side. Should be ~10psi higher

 

[jjdynomite75]

Whats your ambient temp?

Knee jerk says undercharged due to low press on lo side. Should be ~10psi higher

It was around 90. Thanks

 

[Zjohnsonua]

You're undercharged. At 90F and those RPMs your hi side should be 250-270.

There's a table for these pressures and temps in the FSM. There are more general reference tables available on the internet, but they don't account for Toyota's TXV, which is a seriously effective part.