Why does the DTC P0123 for "TPS voltage high" come on when I turn on the A/C? on 2001 Dodge Ram 2500

I have changed the TPS with a new one and cables/connections look and test fine. I cleared the code, the problem still occurs but only when turning on the a/c. The a/c compressor works fine. The a/c system has a low charge but no trouble code shows for same. No other trouble codes are stored or show when the vehicle is run without a/c.

by in Potwin, KS on June 27, 2014
1 answer 2 comments
ANSWER by on June 27, 2014
Professional scanner needed to view live data.... Can watch actual TPS readings!
COMMENT by on July 31, 2015
I have the same problem. I believe it is going to be the PCM. Have you found an answer yet?
COMMENT by on August 01, 2015
After charging the system with R-134a (24oz) the trouble light does not come on wen using the A/C. The A/C is now working well. Can't figure out why the trouble light came on and recorded P0123 when the charge was low. I didn't think there was a sensor for that. I do know they are linked through the idle air control system, but that is just an on/off signal.