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2012 Camry. Need your to help me figure this out

Metal Man on Wed July 01, 2015 12:43 PM User is offline

Year: 2012
Make: Toyota
Model: Camry
Engine Size: 3.5
Refrigerant Type: 134a
Ambient Temp: 85
Pressure Low: Varies
Pressure High: Varies

Sorry this is so long, but please read.

Ok guys need some help with this one. 2012 Camry V6 3.5. Customer say air works random. So pop the hood and see compressor is engaged. I hook up my gages and see both high and low pressures are at static pressure. I ask him to turn off ac and the ac clutch does disengage. So I turn it back on, and the ac clutch engages. Still no change in pressure on either gauge. Both still at static. I have him rev engine to 2000 rpm and hold. After about 60 seconds at 2000 rpm the engine takes a load and I notice the ac compressor has started pumping. Low reading settles at 32 psi and high side at 170 psi. Ac is working great now. I let it run at idle for 10 minutes with no change. Ac works, feels and looks good. At this point we kill the engine, and that's when I notice the pressures are not equalizing as they should. Low side stops at 50 and high side stops at 125. Both stay that way till I open both high/low valves and let the pressures bypass through my ac machine. We then repeat the process with the same results. Ac engages but does not pump until the engine is held at 2000 rpm for a minute or longer. Once it starts compressing all works as it should till we shut down the ac. Then there seams to be a blockage stopping it from equalizing. On start up the ac is engaged pressures are at static all the lines feel ambit temp. Condenser is also ambit temp. Once the ac starts pumping engine bogs slightly, high side lines get hot, low side cold and you can feel the temp change from hot to warm as you run your hand across the condenser.

My gut is telling me it is the compressor but Toyota wants $625 wholesale with out a clutch. Hate to have the guy spend that on a compressor and not be the problem. I'm unfamiliar with this particular compressor but looks like it has some kind of electronic controlled control valve in the back of it. Ring any bells with you guys. Anyone seen a problem like this before? Does not act like an expansion valve stuck to me. Help!!

Edited: Wed July 01, 2015 at 5:20 PM by Metal Man

Metal Man on Wed July 01, 2015 3:49 PM User is offline

Here is a pic of what the compressor looks like.

Metal Man on Wed July 01, 2015 5:24 PM User is offline

Forgot to add that I did recover and weigh 134a. It was only 3 oz. low. I recharged to spec. No change in performance.

AC_Doc on Wed July 01, 2015 5:36 PM User is offline

I notice the ac compressor has started pumping. Low reading settles at 32 psi and high side at 170 psi. Ac is working great now.
Exactly what makes your gut think the compressor is bad??

The engaging & disengaging of the compressor clutch is NOT controlled by the compressor, its controlled by the automobile's computer system.
Something (an AC system sensor) is communicating to the computer that the system is not safe to engage the compressor.

Get a wiring diagram of the AC system and familiarize yourself with the sensor functions.
Could be a low pressure sensor/switch out of tolerance reporting that low side static pressure is too low (out of refrigerant) to start the compressor..
The expansion valve won't cause a failure of the compressor clutch to engage.


Sometimes you must accept things at faith value!

Metal Man on Wed July 01, 2015 5:56 PM User is offline

Best I can tell the compressor clutch is engaging. Our I should say looks like it is. I can see the clutch engage and disengage as the ac switch is turned on and off. Only problem is when you see it engage it doesn't act like its engaged. The compressor is not pumping. The gauges just set at static pressure. Hold the the rpm at 2000 for about 60 seconds and then just like you flipped a switch the compressor starts working. Its weird. Not exactly sure what Im missing here.

And then there is the problem with the pressures NOT equalizing when ac is shut off.

Edited: Wed July 01, 2015 at 5:59 PM by Metal Man

GM Tech on Wed July 01, 2015 10:18 PM User is offline

Variable stroke pump is slow to strokei s what it sounds like from here - or electronically not being commanded to stroke-

No-bleed TXVs are designed not to equalize- so no big deal- newer cars seem to want to use the no-bleeders

The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

Metal Man on Wed July 01, 2015 10:31 PM User is offline

Ok makes sense GM Tech. I'll do some more digging.

Metal Man on Mon July 13, 2015 8:25 PM User is offline

Thought I would update this.

After some more time with the car,I tracked it down to a faulty flow sensor. Code B1479 was in code history. The flow sensor is part of he compressor. I looked everywhere I knew to look but best I can tell the flow sensor is not sold separately. Had to buy a new compressor.

Installed new compressor and everything is back to normal. Ac works great.

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