GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2008 🢒 Yukon - 4WD 🢒 HVAC 🢒 Heating, Ventilation, and Air Conditioning 🢒 Flushing

Flushing NON-HP2

Special Tools

    • J 41447 Leak Detection Dye
    • J 42220 Universal 12V Leak Detection Lamp
    • J 43600 ACR 2000 Air Conditioning Service Center
    • J 45268 Flush Adapter Kit

Important: Flushing with the ACR 2000 is not intended to remove metal from the A/C system.

Flushing is intended to remove the following contaminants:

    • Contaminated polyalkylene glycol (PAG) oil
    • Desiccant, following a desiccant bag failure
    • Overcharge of PAG oil
    • Refrigerant contamination

    Important: Warmer engine or ambient temperature decreases the refrigerant recovery time during the A/C flush procedure.

  1. Recover the refrigerant. Refer to Refrigerant Recovery and Recharging .
  2. Remove the orifice tube. Refer to Expansion (Orifice) Tube Replacement .
  3. Connect the A/C lines with the orifice tube removed.
  4. Remove the A/C compressor. Refer to Air Conditioning Compressor Replacement .
  5. Inspect the end of the suction hose for a suction screen.
  6. Remove the suction screen, if installed.
  7. Install J 45268-4 to the A/C compressor suction hose.
  8. Install J 45268-5 to the A/C compressor discharge hose.

    9. Object Number: 787687 Size: SH
  9. Forward flow refrigerant flushing is recommended for contaminated refrigerant or PAG oil.

    10. Perform the following procedure:

            Important: The filter inside the J 45268-1 is serviceable. Remove and discard the check valve from the filter.

    9.1. Service the filter with ACDelco P/N GF 470, before each flush.

    Connect the J 45268-1 flush filter to the suction port of the J 45268-4 flush adapter.

    9.2. Connect the blue hose from the J 43600 to the J 45268-1 flush filter adapter.
    9.3. Connect the red hose from the J 43600 to the J 45268-5 flush adapter.
  10. Reverse flow refrigerant flushing is recommended for desiccant bag failure. Perform the following procedure and replace the accumulator when the flush procedure is complete.

    11.         Important: The filter inside the J 45268-1 is serviceable. Remove and discard the check valve from the filter.

    10.1. Service the filter with AC P/N GF 470, before each flush. Connect the J 45268-1 flush filter to the discharge port of the J 45268-5 flush adapter.
    10.2. Connect the blue hose from the J 43600 to the J 45268-1 flush filter adapter.
    10.3. Connect the red hose from the J 43600 to the suction port of the J 45268-4 flush adapter.

    Important: Close the valve on the external refrigerant tank, before starting the flush process.

  11. Flush the front A/C system. Follow the instructions supplied with the J 43600 .

    12. Important: Flush the front A/C system before flushing the auxiliary A/C system.

  12. If the vehicle is equipped with rear A/C, flush the auxiliary A/C system separately.

    13. Object Number: 756678 Size: SH
  13. Cut the orifice tube frame and screen, enough to access the end of the orifice tube. Pinch off the orifice tube.

    14. Object Number: 756680 Size: SH

    Important: Pinch off the orifice tube in order to prevent refrigerant flow to the front system during the auxiliary system flush.

  14. Install the pinched orifice tube. Refer to Expansion (Orifice) Tube Replacement .
  15. Remove the auxiliary thermal expansion valve (TXV). Refer to Auxiliary Air Conditioning Evaporator Thermal Expansion Valve Replacement .
  16. Install the J 45268-121.

    17. Important: The auxiliary evaporator core can be flushed without totally reassembling into the auxiliary HVAC module.

  17. Install the auxiliary evaporator core to the A/C lines.
  18. Raise the vehicle. Refer to Lifting and Jacking the Vehicle .
  19. Connect the auxiliary A/C lines to the auxiliary evaporator core.
  20. Lower the vehicle.
  21. Flush the auxiliary A/C system. Follow the instructions supplied with the J 43600 .
  22. Raise the vehicle. Refer to Lifting and Jacking the Vehicle .
  23. Remove the auxiliary A/C lines from the auxiliary evaporator core.
  24. Lower the vehicle.
  25. Remove the J 45268-121.
  26. Inspect the TXV for debris.

    27. Clean or replace as needed.

  27. Install the auxiliary TXV. Refer to Auxiliary Air Conditioning Evaporator Thermal Expansion Valve Replacement .
  28. Remove the J 45268-4 from the A/C compressor suction hose.
  29. Remove the J 45268-5 from the A/C compressor discharge hose.

    30. Important: Flushing will remove all the PAG oil from the A/C system.

    The A/C system must be replenished with the correct amount of PAG oil.

  30. If the removed A/C compressor is being reinstalled, perform the following procedure:
    31. • Drain the PAG oil from the A/C compressor.
    • Rotate the compressor input shaft to assist in draining the PAG oil from the A/C compressor.
    • Add the total system capacity of PAG oil to the A/C compressor. Refer to Refrigerant System Capacities .
  31. If you will replace the A/C compressor after flushing the system, perform the following procedure:
    32. 31.1. Determine if the new service compressor is shipped with PAG oil. Refer to the Refrigerant System Capacities .
    31.2. If the service compressor is shipped with PAG oil, DO NOT drain the new PAG oil from the compressor.
    31.3. Deduct the amount of PAG oil shipped with the service compressor from the amount of PAG oil listed in the capacities table. Refer to Refrigerant System Capacities .
    31.4.  Add the calculated amount to the compressor, as needed.

    Important: Flushing will remove the fluorescent leak detection dye from the A/C system.

  32. Add one bottle of J 41447 directly to the A/C compressor.
  33. Install the A/C compressor. Refer to Air Conditioning Compressor Replacement .
  34. Install a new orifice tube. Refer to Expansion (Orifice) Tube Replacement .
  35. Evacuate and recharge the A/C system. Refer to Refrigerant Recovery and Recharging .
  36. Leak test the fittings using J 42220 .

Flushing HP2

Special Tools

    • J 42220 Universal 12V Leak Detection Lamp
    • J 43600 A/C Service Center
    • J 43600 ACR 2000 Air Conditioning Service Center
    • J 45268 Flush Adapter Kit

ACR2000 (J-43600) Hose Flush Procedure

Important: 

   • The following hose flushing procedure must be performed every time the ACR2000 (J-43600) is used on the hybrid vehicles. It must be completed before the ACR2000 (J-43600) is connected to the vehicle to begin a diagnostic or service procedure.
   • The high voltage (HV) electric air conditioning (A/C) compressor on these two-mode hybrid vehicles uses a polyolester (POE) refrigerant oil instead of a polyalkylene glycol (PAG) synthetic refrigerant oil. This is due to the better electrical resistance of the POE oil and its ability to provide HV isolation.
   • The following hose flush procedure is required to prevent oil cross-contamination. Laboratory testing has shown that flushing the ACR2000 (J-43600) using the following procedure will minimize oil cross-contamination to a negligible amount (<500ppm).
   • Failure to flush the ACR2000 (J-43600) hoses before adding refrigerant to a hybrid vehicle with an electric A/C compressor may result in an unacceptable amount of PAG oil entering the refrigerant system. It may also cause a battery energy control module hybrid battery voltage system isolation lost diagnostic trouble code (DTC P1AE7) to be set. Additionally the A/C system warranty will be voided.
   • The ACR2000 (J-43600) will need to be retrofitted with a J-43600-50 (Hose-ACR2000 Oil Flush Loop) to be able to perform the following procedure. All hybrid dealers will receive a J-43600-50, with installation instructions, which is a component of the hybrid essential tool package. Dealers not included in the hybrid marketing plan and needing to service a hybrid vehicle can obtain the J-43600-50 from SPX Kent Moore, 1-800-GM-TOOLS (1-800-468-6657).
      - The J-43600-50 Retrofit Kit replaces the existing hose mount fittings on the ACR2000. Installation instructions are included to properly update the ACR2000 for hybrid vehicle A/C service.
      - New hybrid compliant A/C refrigerant recharging equipment (GE-48800) will be released in January 2008 for dealers to replace current ACR2000 equipment. GE-48800 meets new SAE refrigerant recovery standard J-2788 and is specially designed for GM hybrid vehicle A/C service.

Before Beginning the Hose Flushing Procedure

  1. Always allow the ACR2000 to complete the hose flush cycle to assure that all oil and refrigerant is removed from the hoses and the ACR2000 flow control circuit.
  2. Assure the ACR2000 has at least 4.08 kg (9 lb) of chargeable refrigerant before proceeding.
  3. A Low Filter Flow message displayed during the hose flushing process indicates that the hose couplers are not connected or open.

Hose Flushing Procedure

  1. Connect the ACR2000 service hose couplers to the J-43600-50 hose flush adapter fittings and open the service hose coupler valves.
  2. Power on the ACR2000.
  3. If there is positive pressure in the ACR2000 service hoses, press START to recover the service hoses. If there is 88-98 kPa (26-29 Hg) of vacuum showing on the display screen, skip to step 7.
  4. Press Vacuum.
  5. Press Start. Allow the vacuum program to run until the display screen shows between 88-98 kPa (26-29 Hg).
  6. Press Pause.
  7. Press Main Menu.
  8. Press Scroll Menu.
  9. Press Oil Flush.
  10. Press Next.
  11. Enter 03:00 (for a three minute flush) and press Start.
  12. The ACR2000 will now flush the service hoses for three minutes and then recover the refrigerant
  13. Close the ACR2000 service hose couplers and remove the J-43600-50 hose flush adapter.
  14. The ACR2000 can now be connected to the hybrid vehicle to perform the A/C system diagnostic or service procedures.

Important: Flushing with the ACR 2000 is not intended to remove metal from the A/C system.

Flushing is intended to remove the following contaminants:

    • Contaminated polyolester (POE) oil
    • Desiccant, following a desiccant bag failure
    • Overcharge of POE oil
    • Refrigerant contamination

    Important: Warmer engine or ambient temperature decreases the refrigerant recovery time during the A/C flush procedure.

  1. Recover the refrigerant. Refer to Refrigerant Recovery and Recharging.
  2. Remove the orifice tube. Refer to Expansion (Orifice) Tube Replacement.
  3. Connect the A/C lines with the orifice tube removed.
  4. Remove the A/C compressor. Refer to Air Conditioning Compressor Replacement.
  5. Inspect the end of the suction hose for a suction screen.
  6. Remove the suction screen, if installed.
  7. Install J 45268-4 to the A/C compressor suction hose.
  8. Install J 45268-5 to the A/C compressor discharge hose.

    9. Object Number: 787687 Size: SH
  9. Forward flow refrigerant flushing is recommended for contaminated refrigerant or POE oil.

    10. Perform the following procedure:

            Important: The filter inside the J 45268-1 is serviceable. Remove and discard the check valve from the filter.

    9.1. Service the filter with ACDelco P/N GF 470, before each flush.

    Connect the J 45268-1 flush filter to the suction port of the J 45268-4 flush adapter.

    9.2. Connect the blue hose from the J 43600 to the J 45268-1 flush filter adapter.
    9.3. Connect the red hose from the J 43600 to the J 45268-5 flush adapter.
  10. Reverse flow refrigerant flushing is recommended for desiccant bag failure. Perform the following procedure and replace the accumulator when the flush procedure is complete.

    11.         Important: The filter inside the J 45268-1 is serviceable. Remove and discard the check valve from the filter.

    10.1. Service the filter with AC P/N GF 470, before each flush. Connect the J 45268-1 flush filter to the discharge port of the J 45268-5 flush adapter.
    10.2. Connect the blue hose from the J 43600 to the J 45268-1 flush filter adapter.
    10.3. Connect the red hose from the J 43600 to the suction port of the J 45268-4 flush adapter.

    Important: Close the valve on the external refrigerant tank, before starting the flush process.

  11. Flush the front A/C system. Follow the instructions supplied with the J 43600 .

    12. Important: Flush the front A/C system before flushing the auxiliary A/C system.

  12. If the vehicle is equipped with rear A/C, flush the auxiliary A/C system separately.

    13. Object Number: 756678 Size: SH
  13. Cut the orifice tube frame and screen, enough to access the end of the orifice tube. Pinch off the orifice tube.

    14. Object Number: 756680 Size: SH

    Important: Pinch off the orifice tube in order to prevent refrigerant flow to the front system during the auxiliary system flush.

  14. Install the pinched orifice tube. Refer to Expansion (Orifice) Tube Replacement.
  15. Remove the auxiliary thermal expansion valve (TXV). Refer to Auxiliary Air Conditioning Evaporator Thermal Expansion Valve Replacement.
  16. Install the J 45268-121.

    17. Important: The auxiliary evaporator core can be flushed without totally reassembling into the auxiliary HVAC module.

  17. Install the auxiliary evaporator core to the A/C lines.
  18. Raise the vehicle. Refer to Lifting and Jacking the Vehicle.
  19. Connect the auxiliary A/C lines to the auxiliary evaporator core.
  20. Lower the vehicle.
  21. Flush the auxiliary A/C system. Follow the instructions supplied with the J 43600 .
  22. Raise the vehicle. Refer to Lifting and Jacking the Vehicle.
  23. Remove the auxiliary A/C lines from the auxiliary evaporator core.
  24. Lower the vehicle.
  25. Remove the J 45268-121.
  26. Inspect the TXV for debris.

    27. Clean or replace as needed.

  27. Install the auxiliary TXV. Refer to Auxiliary Air Conditioning Evaporator Thermal Expansion Valve Replacement.
  28. Remove the J 45268-4 from the A/C compressor suction hose.
  29. Remove the J 45268-5 from the A/C compressor discharge hose.

    30. Important: Flushing will remove all the POE oil from the A/C system.

    The A/C system must be replenished with the correct amount of POE oil.

  30. If the removed A/C compressor is being reinstalled, perform the following procedure:
    31. • Drain the POE oil from the A/C compressor.
    • Add the total system capacity of POE oil to the A/C compressor. Refer to Refrigerant System Capacities.
  31. If you will replace the A/C compressor after flushing the system, perform the following procedure:
    32. 31.1. Refer to the Refrigerant System Capacities.
    31.2. DO NOT drain the new POE oil from the compressor.
    31.3. Deduct the amount of POE oil shipped with the service compressor from the amount of POE oil listed in the capacities table. Refer to Refrigerant System Capacities.
    31.4.  Add the calculated amount to the compressor, as needed.

    Important: Flushing will remove the fluorescent leak detection dye from the A/C system.

  32. Replace the A/C accumulator assembly. Refer to Air Conditioning Accumulator Replacement.

    33. Note: The serviced accumulator assembly is manufactured with POE fluorescent leak detection dye wafer inside.

  33. Install the A/C compressor. Refer to Air Conditioning Compressor Replacement.
  34. Install a new orifice tube. Refer to Expansion (Orifice) Tube Replacement.
  35. Evacuate and recharge the A/C system. Refer to Refrigerant Recovery and Recharging.
  36. Leak test the fittings using J 42220 .