sarahsjeep777

we recharged the AC in my jeep cherokee and now its throwing mulitiple codes and wont shift into overdrive

When I clear the codes off and the check engine light goes off it shifts and drives fine. When I restart it the check engine light comes back on and wont shift until i clear it again.

the four codes
p1491 which is radiator relay fan
P0443, there has to be a problem with the purge control CIRCUIT
P0138, the book says "02 sensor circuit high voltage downpipe"
P0705 JEEP - Transmission Range Sensor Circuit Malfunction

we were going to replace the transmission sensor but it doesnt have a problem going into gears and it shifts perfectly when the codes are cleared. The AC still doesnt work but there is absolutely no problem idiling or driving.

has anyone had this problem or have any insight?

sarahsjeep777

i just found this on a google search


The 42RE transmissions use a single sensor (located on the overdrive gear case, over the park gear). The 45RFE / 545RFE transmissions use two sensors, an input speed sensor and an output speed sensor. Both are the same part number.



The Input Speed Sensor provides information on how fast the input shaft is rotating. As the teeth of the input clutch hub pass by the sensor coil, an AC voltage is generated and sent to the TCM. The TCM interprets this information as input shaft rpm.
The Output Speed Sensor generates an AC signal in a similar fashion, though its coil is excited by rotation of the rear planetary carrier lugs. The TCM interprets this information as output shaft rpm.
The TCM compares the input and output speed signals to determine the following: Transmission gear ratio
Speed ratio error detection
CVI calculation

Radi

What year cherokee?

sarahsjeep777

It's a 2000 4.0 Cherokee sport

9XJSPORT7

Well you have an AW4 trans...the trans you came up with in google are for a grand cherokee not a cherokee.....my bet is the Netural Safty Switch...mine does the same thing...I can clear the codes and its fine and I can come to a stop and it wont go at all unless I shift it down in into first gear manually......you can pull it off and clean it as its cheaper than the $200 and some dollar switch...their is a write up some where if you search....It sounds like its dirty

sarahsjeep777

I found the write up on the trans sensor. Did yours not shift into overdrive? Or just not start? It was weird this just happened after trying to recharge the AC.