stone4779

2007 Aveo LS w/90K miles. Flashing "HOLD" light, P0118 DTC, no other codes. Wont shift into overdrive either.

The car starts right up with zero to little effort, sometimes it revs up a little bit on initial startup then drops back to a normal idle fairly quickly(5 seconds or so at worst).

It doesnt run hot, and doesnt run particularly sluggish..although Im used to my V12 twin turbo, so to me its slow as heck, but doesnt feel like its struggling really, so I think it runs OK, especially for what its been through lol.

After a couple seconds after intial startup, the "HOLD" light will begin to flash regularly. I tried disconnecting the battery to reset the codes on the computer, as well as I used a handheld scanner to clear the codes at Autozone.

It still flashes the "HOLD" light.

This leads me to believe that it is in some sort of limp home mode or safety mode.

I ran the codes before and I always got P0118, which from what I have gathered, a code thrown when the 5v signal from the coolant temperature sensor is high. (the one located on the back of the cylinder head near the intake, there's TWO ECT sensors.)

This led me to believe even more that maybe it thinks its overheating, and its keeping the transmission from getting into overdrive, to prevent the transmission components from failing from the "overheating" engine.

I went ahead and bought a new coolant temperature sensor, and replaced it(pain in the *** btw) and reset the codes.

Still no change after that. I WOULD say its a bad connection in the wire to the censor, but in that case it would more likely be LOW(er) voltage due to the bad connection, not higher...unless its crossed with another exposed wire, which is very, very unlikely. Im going to recheck the wire again just in case,


but does anyone have any ideas? Its my girlfriends car, and its been sitting since November 2013 and she still to this day does not have a car. We would really really really appreciate any help I could get...in the meantime Im a chauffeur 3x a day lol


Thanks


-SIDE NOTE: I tried to log the voltage of the ECT sensor with hptuners, but apparently this car is NOT supported for even scanning and logging data..which is super lame. Maybe I can try logging the voltage at the PCM connector? I would need to find the pinout diagram for this particular PCM