A/C compressor don´t engage

[Malachias]

Olds 98 Regency 1991 with 62.000ml on it

Checked all A/C fuses. Grabed in dash self diagnoses code # 138.
The air comes ok in all the vents but the compressor clutch still off.
Any help or tip will be welcome.
Malachias (BRAZIL)

[maxwedge]

Low freon can cause this for starters and/or temps below 40 which is normal.

[Malachias]

Dear Maxwedge: Thanks for your quick replay.
The low freon code is 66 or 166. The temp here i Brasil is always hot.
The code that I got is 138 (Serial data line failure with PCM).
Do you know what it means?
Thanks a lot in advance.
Malachias

[maxwedge]

This usually means the Pcm has lost comm. with the BCM

[Malachias]

Dear Maxwedge:

Is the Pcm a Programmer module and a BCM a Body Control Module?
If yes, what you advise me to do?
Thanks
Malachias (BRAZIL)

[maxwedge]

Confirm the system is fully charged using an A/c gage set. Pcm is the main controller not the programmer. ( Powertrain control module)

[Malachias]

Dear Maxwedge:
You was right; even I had grab a 138 code # in the self diagnose A/C display
I followed your advise and did a Freon level recheck again (Low freon code is 66) and found my sistem with a half of charge wiht a litlle leakeage at the high pressure valve. I fixed the valve, recharge the Freon and the cluntch compressor start to work. No more headake problem solved.
Thanks a lot for yours helpfull tips.
Malachias (Brazil)

[maxwedge]

You are welcome.