Durango 2WD V8-4.7L Flex Fuel (2009)
Transmission Position Switch/Sensor: Description and Operation
Transmission Range Sensor - Operation
OPERATION
The Transmission Range Sensor (TRS) communicates shift lever position to the TCM as a combination of open and closed switches. Each shift lever
position has an assigned combination of switch states (open/closed) that the TCM receives from four sense circuits. The TCM interprets this information
and determines the appropriate transmission gear position and shift schedule.
There are many possible combinations of open and closed switches (codes). Seven of these possible codes are related to gear position and five are
recognized as "between gear" codes. This results in many codes which should never occur. These are called "invalid" codes. An invalid code will result
in a DTC, and the TCM will then determine the shift lever position based on pressure switch data. This allows reasonably normal transmission operation
with a TRS failure.