Thread: P1810 Trouble Code - TFP Valve Position Switch Circuit

This is my roomate's post from the regal forum. He hasn't gotten much help there, so I figured I'd bring the question here. Trannyman, maybe you can pin-point this one.

Quote: Trumpetrhapsody
"Just yesterday the car started throwing the P1810 trouble code. Looked it up and it indicates that is the TFP Valve Position Switch Circuit.

Before the trouble code threw, I noticed that my shifts were much firmer, harsh actually. It's most noticeable accelerating through the 1st & 2nd shifts.

Searched that code here, and nothing turned up. Any ideas? I'd prefer to get some opinions before I just go replace the sensor, as that wouldn't help if the tranny is screwed."


Today, he drove a 60 mile round trip. The problems seemed to get worse as the trans got hotter. Now, the car seems to lurch at low RPM/load acceleration. Sometimes the car can't figure out what gear to be in at lower speeds, and the problem worsens as it's driven for extended periods of time.

Also, it seems to stay in a higher gear (3rd maybe?) and clicks when accelerating out of slower turns/corners.

Without doing some investigating with a scan tool to watch trans data I cant be of too much help, but the common causes here are a bad fluid pressure switch manifold or wiring and may require dropping the trans down to remove the side cover to replace the pressure switch manifold if it is at fault. He could try unplugging and plugging back in the trans connector to see if that helps. If you or he has a scan tool or can borrow one it will help out, then you can verify that the pcm is seeing the correct gear internally that matches the shifter.