Trouble Code P1640 QDM 1

[Joe8888]

1994 Pont. Transport has trouble code P1640 QDM 1. It's control module circuit A. Can anyone explain this in English so I will know where to look.AC compressor started squelling last week and needs replacing, can this have anything to dowith code. Haynes manuals useless.

[elroyas]

Hi,

Any symtoms?
I had this code together with other malfunctions.
Turned out to be the ignition switch.

Andy

[Joe8888]

No symptoms at all. Ignition switch was new last year. Only thing different was the AC pulley bearing noise.

[Joe8888]

Well, problem solved. Turned out that when the AC compressor bearing seized there was an overload on that circuit. Everytime car was started there was a heavy draw on the ac power circuit and it just wanted help. Changed AC compressor (pain), reset check engine light, no more trouble. Andy, thanks for answering.