On 8/22/2013 8:33 PM, Oppie wrote:
> Predictably, the morning that we were supposed to leave on vacation, the
> Vue started shifting very roughly. I had filled the tank the night
> before so suspected bad fuel. Put in a can of drygas and hit the
> highway. About 10 miles into the 200 mile trip, the MIL light came on.
> Pulled over and started pulling fuses (the lw300 ECU could be reset by
> pulling the controls B+ fuse). No dice, couldn't find a fuse that would
> turn off the light. Drove all the way with the transmission slamming
> from gear to gear. It was like the torque converter stayed locked up.
> Interesting that the shifter normally defaults to 3rd gear when you
> shift to manual and you can shift up or down from there. Now the manual
> defaults to 4th gear and the up/down buttons are not functional.
>
> Finally made it to destination (enduring wife's diatribes that we bought
> a POS) and after unloading the car, fished out my AutoTap tool and
> laptop. Showed P0842 "transmission fluid pressure sensor "A" circuit
> Low." I haven't been able to make sense of this yet. Did a reset of the
> fault codes and car is driving fine now. Drove it for about 50 miles
> today and light has not come back on. It likely will so looking for
> possible causes.
>
> 2009 Vue XE with 2.4L EcoTec and 4T45 base model transmission

Either the sensor is flaky or pressure switch manifold is flaky.

If you have an Android phone or tablet you should buy Torque Pro from
the Play store and buy a Bluetooth ELM327 module for the OBDII socket;
for less than $20, you'll always have an OBDII scan tool with you.

<https://play.google.com/store/apps/details?id=org.prowl.torque&hl=en>
<http://dx.com/s/142679>

Unfortunately, due to Apple not supporting the proper Bluetooth
protocol, there's no equivalent app for iOS.