I have code 1810 on my 99 Grand Prix GT, after doing a major gasket update/change (Lower Intake Manifold Gasket, Upper Intake Manifold, Valve cover gaskets, Water pump w/gasket; the coils and the catalytic converter also went bad with the constant steam cleaning of the cylinders so I also replaced those; when I unplugged the temp sensor and map sensors they fell apart so I also replaced those).
I googled it and found:
1810 transmission fluid pressure valve position switch circuit
I've checked my transmission fluid and taken a good look at all the connectors and wiring. I haven't got under the car yet, but everything looks in order so far.
I did a search and it seems that code 1810 is rare, and I still can't figure out why the 1810 code. The Service Engine Soon light is annoying, otherwise it wouldn't bother me. Please help.
