I have a 1990 Olds Toronado with the digital dash. The dash displays that "AC very low on refrigerant". The compressor clutch won't engage. I have evacuated the AC system and put 16 oz. of R12 refrigerant in the system which is what the capacity is on this vehicle. The AC clutch still wont engage. Is there a trick to getting the clutch to work. This car has not been driven much in the last few years it has 57,000 actual miles on it and I had to put some freon in it about 3 years ago with no problem.


thanks in advance, Mike P.

 

Make sure the A/C is turned OFF.You have to first clear the code in order for the compressor to engage.It is a safety feature on that car so the compressor will not burn out. After you clear the code,add/connect the first can of "STUFF". Make sure you puncher the hole in the can before you turn on the A/C,make sure you leave the valve on the can/hose open so that when you turn on the A/C the "Stuff" is sucked in. You will then hear the compressor engage,but not for long,it will disengage soon because of low on refrigerant.You will have to repeat the first step of clearing the code again. Then you add the next can of "STUFF" and there after. But most importantly you need to know how to clear the code. Keep reading:





The diagnostics are very useful in identifying faults in the car's electronic circuits. By making careful use of the options available, it is possible to narrow down the location of faults.


I have a 1991 Toronado Trofeo with the VIC option, hence these notes apply directly to that car. However, the non-VIC car is also covered. As far as I am aware any GM car (not Cadillac) with "tempmatic" (automatic, you set the temperature, the car does the rest) air conditioning control from this era has similar controls. The Gen IV cars were made from 1985 to 1992. The exact codes available will vary by year.


The diagnostic system uses the display on the IPC for data values and the VIC or a/c unit for mode displays. The system is driven by the buttons on the a/c unit or soft buttons on the VIC.


To use diagnostics you need the ignition on. The engine does not need to be running, some options are not available depending on whether the engine is running or not. If you have a serious fault such that any of the data highway, IPC, VIC (or a/c) unit, or Body Control Module (BCM) are not working, you won’t be able to enter diagnostics. Try a scan tool instead.


To enter diagnostics, switch the ignition on and press "Warm" and "Off" simultaneously for about 4 seconds. The "warm" button is a soft button on the VIC, the "off" button is the hard off button by the climate control button. Without the VIC, use the a/c "warm" and "off" buttons. Don't do this as the driver of a moving car. You can run diagnostics while the car is being driven.





Any stored codes will be displayed (on VIC press "No" if you don't want to wait), note them down if you are interested. Ideally you won't have any.





When all codes have been displayed, you get the "ECM?" prompt (on the IPC).





Once in diagnostics, you have a number of options. You have to keep an awareness of which level you are at. So if you start with the ECM (a level 1 item) and say "Yes", you get ECM options (level 2). The first is "ECM Data?". If you say "Yes" to that, you get the various ECM variable sensor data (level 3). Pressing "Yes" now takes you from one data input value to the next (still level 3). Pressing "No" here takes you backwards through the same list (level 3). If instead you pressed "No" to the "ECM Data?" question, diagnostics prompts with the next ECM option, "ECM Inputs?" (level 2). Pressing "Yes" allows you to cycle through the on/off input data, but if instead you press "No" again, you get offered the next item which is "ECM Outputs?". To go up a level you press the "Levl" button, to stay at the same level but be offered the next option you have to take the "No" route and to go down to a lower level you have to press "Yes". In the Override page, you can force values up and down using the slew buttons. I won't explain the snapshot function, it is too complex for this page, but is not too difficult to work out.