Ac Compressor not turning on

Discussion in 'Prius v Care, Maintenance and Troubleshooting' started by Haplo888, May 13, 2019.

  1. Haplo888

    Haplo888 New Member

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    I got some pure R134a refrigerant (no oil) and a hose with a gauge to try to fill our 2008 gen2 prius. It is blowing warm.

    But when I connected the gauge it shot up to 90psi (L side) and never dropped, making me think the compressor is not turning on. The same gauge does go up and down on another car.

    A mechanic mentioned the compressor might not turn on at all if it is too low on coolant. But I am a bit apprehensive about adding coolant when the psi is so high.

    Is there much risk in adding some coolant to see if I can get the compressor to come on?

    Thanks
     
  2. Haplo888

    Haplo888 New Member

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    Can somebody move this to the gen2 forum for me? I had searched for similar topics before posting and ended up here after reading a different one.
     
  3. rjparker

    rjparker Senior Member

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    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.
    5109BA16-5D15-433A-8259-F53FEFE0E190.jpeg R
     
    #3 rjparker, May 14, 2019
    Last edited: May 14, 2019
  4. rjparker

    rjparker Senior Member

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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.
     
    #4 rjparker, May 14, 2019
    Last edited: May 14, 2019
    Raytheeagle likes this.
  5. Haplo888

    Haplo888 New Member

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    Following the instructions you posted, after a diagnostic phase, it gave me blinking code 76, though that's not on the list. I am having trouble finding a repair manual in the link you first posted, only the owners manual from Toyota's website.
     
  6. rjparker

    rjparker Senior Member

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    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.

    6F37572A-A2D5-4381-B21F-98D79FA81A94.jpeg
     
    #6 rjparker, May 15, 2019
    Last edited: May 15, 2019
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