Ac Compressor not turning on

Not much experience with the ac system as it is normally very reliable. You probably need to go to the toyota techinfo site and check the online repair manual for troubleshooting the ac system. Since it is a three phase electric compressor it is network controlled and has its own controller called an ac amplifier. I believe there is a diagnostic code accessible through special keypresses. Once you have those codes the online repair manual will decode them and how to proceed. The link gives more info on the techinfo site. Toyota Service Information and Where To Find It | PriusChat

The drawing below is from a 2012 gen 3 but will give you an idea of the sensor.
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Here is a procedure I located for getting the ac codes

TROUBLE SHOOTING
SELF-DIAGNOSTICS
An Electronic Control Unit (ECU) within A/C-heater control panel monitors system circuits and stores trouble codes in memory if problems are detected. All codes, except Codes 22 and 23, are stored in memory. Malfunction is current if Code 22 or 23 is displayed. To retrieve stored codes, see RETRIEVING CODES. Codes are displayed at temperature display.

RETRIEVING CODES
1) Simultaneously press and hold AUTO and RECIRCULATE switches on the steering wheel. Press Start and go to Ready. Turn AC on as some code appear only when running.
2) A/C system will enter self-diagnostic mode. To end indicator check, press and release OFF switch. Read codes at temperature display.
3) If trouble code is displayed, proceed to appropriate trouble shooting procedure. See DIAGNOSTIC CODE IDENTIFICATION table. Codes are displayed in ascending order.

Code Diagnosis
00 ................................................ Normal
11 (1) ............. In-Vehicle Temperature Sensor Circuit
12 (2) ................ Ambient Temperature Sensor Circuit
13 ................. Evaporator Temperature Sensor Circuit
14 .................... Coolant Temperature Sensor Circuit
21 (3) .............................. Solar Sensor Circuit
22 (4) .................... Compressor Lock Sensor Circuit
23 (4) ........................... Pressure Switch Circuit
31 .................. Air Mix Door Position Sensor Circuit
32 ................ Air Inlet Door Position Sensor Circuit
33 ............... Air Outlet Door Position Sensor Circuit
41 ....................... Air Mix Door Servomotor Circuit
42 ..................... Air Inlet Door Servomotor Circuit
43 .................... Air Outlet Door Servomotor Circuit

(1) - If in-vehicle temperature is -4 F (-20 C) or less,
Code 11 may set even though system is normal.
(2) - If outside air temperature is -58 F (-50 C) or less,
Code 12 may occur set though system is normal.
(3) - If testing is done in a dark area, Code 21 may set even though system is normal. Shine a light at solar sensor and recheck codes.
(4) - Malfunction is current. Code is not stored in memory.

ACTUATOR CHECK
1) Perform step 1) of RETRIEVING CODES. When system enters self-diagnostic mode, press recirculated air button. Each mode door, motor, and relay will operate at one-second intervals. Press fresh air button to display codes one at a time, and perform step-by-step actuator check.
2) Check airflow and temperature by hand. Tone will sound each time display code changes. Each display code is associated with a system operating condition. Press OFF button to cancel actuator check mode.

 

A little more googling:

“Not a good one. It says there is an A/C Inverter Load System Malfunction (code 76). This can be caused by a refrigerant leak or overfill, a problem in the condenser fan circuit, or lastly a compressor lock.”

...and

“When I brought it in for service, their first diagnosis was refrigerant loss so they attempted to bypass the low refrigerant failsafe. They couldn't get the compressor to cycle back on to take in more refrigerant and a leak detecting dye. So it is sort of pointing to the compressor being at fault.”

...and

“Compressor replaced, system evacuated and recharged. Tech said no debris noted in system flush. Cooling quite nicely now. New (used) compressor sounds quieter. I asked about what would be done with my old compressor and they said it would be returned as a core. Not torn apart to see what caused the failure.“

So its either take it in for a Toyota diagnosis, try to bypass the low pressure switch (find procedure at techinfo) and or go shopping on ebay (but somebody would still need the procedures). I think if it was the pressure sensor you would have seen code 22 or 23.

 

My code 76 wound up being the AC Compressor required replacement. Used a weekend sale bucket 25% off salvage yard genuine Toyota along with locally source ND14 POE equivalent oil and R-134a. Catastrophic failure of the og one. Here's what that looked like: 2005 Gen2 (05-09) Prius AC Compressor Replaced DTC's B1421 & B1476 - YouTube

 

My 2 cents started here: please help. cooling fans wont come on | PriusChat

 

So you just took this compressor off put in another one use the software to call it up or turn it on with or without gas in it to see if it would work and then what continued to flush the system vacuum it down wow I would have think you would have heard all that metal bouncing around inside your compressor but oh well.

 

I can confirm that the link rjparker posted does explain several different ways of accessing the repair manual, through Toyota's site and other parties. If you got to where the owners manuals are, it sounds like you were very close on Toyota's site. The owners manuals are available without subscription so they're the first things you see.

 

Haplo888 hasn't posted since 2019. I supposed it's "for the record" anyway though.

 

@Tombukt2 Removed the AC compressor from the salvage yard car being carful to not let anything get into the hoses as I left those on as a buffer to help keep debri out of the compressor.

To test, I unplugged the plug at the inverter converter assembly (PCU) and plugged in the salvage yard one very briefly with the max cold AC and high fan settings to make certain sounded OK. I had rags or towels over the holes, I forget which offhand. More so to prevent dust from getting in the salvage yard compressor.

Being the installed compressor didn't turn on and only made a weird noise upon my taking ownership, I never heard the performance prior nor did we hear perform with the certified HVAC person assuring was filled enough so would properly turn on. Plus tested the electrical characteristics per the service manual of the compressor and seemed OK offhand if I recall correct though maybe was bad on a phase as I forget at the moment and plus reading around what the electrical characteristics of the pressure sensor was supposed to test and seemed to be good.

Decided to pump down the system so could disconnect the lines without wasting gas. Keep in mind that the POE oil seems like some nasty product that you don't want to touch, so glove up.

Then I forget offhand all the details; though there was the draining of the bad compressor to get a sense of oil volume in that still, tear down of the pump since my HVAC person wanted to see what actually happened, careful assembly with the salvage yard pump after adding oil, flushing system, testing for leaks, purging a few times with nitrogen and adding refrigerant to correct Toyota specs. Keep in mind I might be out of order in regards to steps followed with what I noted in regards to flushing, testing for leak and the nitrogen purges.

No software was required other than the as-found and as-left Toyota Prius system that was all plug and play with no anything unique done; plus the fancy vacuum gage, fancy scale, fancy vacuum and compressor pumps and fancy manifold firmware imbedded in those tools.

 

Is there any confusion that the Prius V section is discussing repair A/C of the Prius GEN2?

 

There are a few differences in the systems:

• In gen 2, the A/C Inverter is part of the inverter assembly under the hood, but in gen 3 it's part of the compressor itself
• so in gen 2 there's a 3-conductor orange cable from the inverter to the compressor carrying 3-phase AC, while in gen 3 it's a 2-conductor orange cable carrying DC
• in gen 3, the pressure sensor is a real transducer (so you can read the actual pressure on a scan tool), where in gen 2 it was just a switch ("too low or too high" vs. "probably ok I guess").

Beyond those differences, the systems are pretty similar.