I ran into a problem when my autotrac transfer case locked into 4low (original thread (http://dieselplace.com/forum/forum_posts.asp?TID=6227&PN=1)). I scanned the ecu and got the following DTC:


P1810 TFP Valve Position Switch Circuit/ Transmission 4-Wheel Drive Low Indicator Short Circuit To Battery


Does anybody have any insight on how to resolve? Would this code be triggered if the 4low sensor went bad? About where would this sensor be located?


Thanks in advance.

<H5>Circuit Description</H5>


The automatic transmission fluid pressure (TFP) manual valve position switch consists of five normally-open pressure switches. The powertrain control module (PCM) supplies battery voltage to each range signal. By grounding one or more of these circuits through various combinations of the pressure switches, the PCM detects what manual valve position has been selected and compares the actual voltage combination of the switches to a TFP manual valve position switch combination chart stored in memory.


The TFP manual valve position switch cannot distinguish between PARK and NEUTRAL because the monitored valve body pressures are identical in both cases. With the ignition ON and the engine OFF, D2 is indicated. When the transmission 20-way connector is disconnected, the ground potential for the three range signals to the PCM is removed, and with the ignition ON, D2 is indicated.


If the PCM detects an invalid state of the TFP manual valve position switch circuit by deciphering the TFP manual valve position switch inputs, then DTC P1810 sets. DTC P1810 is a type B DTC.








Since you need to be in neutral to shift in and out of 4LO, it's possible the PCM isn't seeing neutral because of this fault. You really need a scan tool to see transmission data to diagnose this code.

I have an Actron CP9135 (http://www.actron.com/cgi-bin/web_store.cgi?page=cp9135.htm&amp;cart_id=) OBD-II scanner that I rented to pull the codes. Is this scanner sufficient to see the transmission data you are asking about? Edited by: SuperTuscan

most likely not, it appears to just be a code reader. will need something that you can look at component data with