p1780 - Toyota Nation Forum : Toyota Car and Truck Forums

99lexus · 11-08-2007, 06:17 AM

Can anyone tell me what exactly a p1780 code is and how can i fixt it . The car is a 99 lexus es300 . Im having a hard time figuring it out ...

thanks
jose

ShawnM · 11-08-2007, 07:35 AM

A p1780 is a code for the neutral safety switch that is mounted on the tansmission. This switch basically tells the engine control computer what gear you have the car in. The code sets when it recieves conflicting signals from the switch, such as being in park and reverse at the same time. The switch or the wiring could be the problem. Its more likely the switch but its best to have it checked first. The switch runs anywhere from $150 to $250 depending on which type it is.

99lexus · 11-08-2007, 08:46 AM

by the way i had a wire that was pinched in the trunk and i fix it .... could that have caused the code to show up ....... it used to make my reverse light on the instrument panel light up and now it does not

ShawnM · 11-08-2007, 11:18 AM

It sure could. I ran into a similar situation on an LX 470. The computer thinks the car is in reverse and drive at the same time so it throws the neutral safety switch code since it cant possible be in both those gears at the same time.

99lexus · 11-08-2007, 01:29 PM

thanks for the help ....

greatly appreciated

98Lexus_210k+ · 01-14-2008, 08:19 AM

99lexus...How hard was it to fix that wiring problem on the tail lights? I just bought a 98 lexus that has the same problem. The trunk lid mounted lights don't work and it throws the same code. If you could give me an idea of where to look for that wire pinch, it may save me some search time. Thanks!
Good job fixing the problem by the way. Seeing this post saved me a lot of heartache. My wife was pretty discouraged about that check engine light.

99lexus · 01-14-2008, 04:32 PM

hey the pinch wire was by the side in the trunk ... there are wires running through a black protective plastic there i took that apart and went through all the wires mine was a white colored wire that was broken once i connected them again my check engine light went away and the car has been fine since them ... good luck ....

98Lexus_210k+ · 01-15-2008, 07:52 AM

I'm going to give it a try tonight. Hopefully it will be in a similar location. It seems like a common problem from my research. Thanks for the reply!

98Lexus_210k+ · 01-16-2008, 12:19 PM

I got in there last night and someone had just taped the wires together. I put a connector between the two that were broken and everything came on. The check engine light went off too. Thanks for the help!