Hi :

I have a 2002 LS430, and just today, I started experiencing a low speed lurch. Have owned the vehicle for 6 months, and I have never experienced it before.

Also, the CEL is now on, and using my ODBII reader, I see that is a P1780, which refers to a PNP switch issue.

This may be a coincidence, but the parking assist indicator no longer works either. It apears to start up ok, but I dont get any beeps or indicators flashing anymore.

This all started tonight.

Something odd is going on, and just wondering if anyone has seen this before.

Thanks
Mike

 

Your Park/Neutral Position (PNP) Switch is either defective or in need of adjustment. Try this...

Drive your car to an open area, and try to start it while the shifter is in "R" or "D". If you can get your starter to engage/move, you have a bad or out-of-adjustment PNP switch.

 

Hi :

Thank you for your response.

I did do that, and it does not start.

I'm thinking it might have been triggered by the "lurching". Thinking I will reset the CEL, and see if it happens again.

Mike

 

On other cars, the park/neutral position switch is called the neutral safety switch or transmission range sensor. It attaches to the side of the transmission and is somewhat exposed to water and road salt.

P1780 is a common problem with older Honda cars - never heard of it on an LS430 - what year is yours and how many kms?

I've fixed it on a 2002 Accord V6 by removing the front left wheel, unbolting the range sensor holding bracket, then unbolting the range sensor cover, and then you can pull the switch off for cleaning. The symptoms were that the reverse lights wouldn't go on and that the indicator on the dash doesn't show some/all the gears.

The screws holding the unit together were too rusted to unscrew, so instead of taking apart the switch and blasting it with electrical contact cleaner from the inside, I sprayed inside the circular moving part as I moved it back and forth through its entire range of motion. It takes several minutes of spraying and spinning the switch back and forth. It would have been a more thorough job if I was able to clean it from the inside.

When reinstalling the switch, you will need your car to be in neutral and the wheels chocked/e-braked for safety. To align the circular notch properly, turn with a flathead screwdriver just until it falls into a click/groove - this indicates the neutral position. You will also want to test each gear on the shifter before fully reassembling everything to ensure that your cleaning job was successful.

 

Hi :

The problem was a bad alternator, resulting in insufficient current.


Replaced it, and problems have all gone away.

Thanks to everyone for their help.

Mike