CVT torque converter not locking in cold weather

[phmichel]

Anyone know if ambient temp is part of the formula used by the CVT computer to calculate when the Torque Converter locks after first acceleration?

I have a 2013 S model. Above 45 degrees F it needs about 1 min after startup and the TC will lock up right after starting off, or it will run about 1500 RPM at 50mph. We just had our first couple days of cold here in NW Oregon (in the mid 20's). Let it warm up about 3-4 mins but the RPMs at 50mph stayed at 2000+ and wouldn't drop till after the gauge showed warm (about 10 mins on the road).

May need to incorporate Stricken's cardboard radiator shield

Would like to hear your input...

[ImStricken06]

how do you know there is true lock-up? are you running a scantool?

[phmichel]

how do you know there is true lock-up? are you running a scantool?

No Scan tool. You can feel and see it. Normally, if I take it easy on the gas when first accelerating, it starts rolling then a few seconds later the RPMs drop and you can feel the TC lock. I like that about the CVT. But its taking longer in cold weather. Trying to understand why.

[ImStricken06]

how do you know there is true lock-up? are you running a scantool?

No Scan tool. You can feel and see it. Normally, if I take it easy on the gas when first accelerating, it starts rolling then a few seconds later the RPMs drop and you can feel the TC lock. I like that about the CVT. But its taking longer in cold weather. Trying to understand why.

that doesnt mean its 100% locked. what you are feeling is the cvt going into a lower gear ratio faster, to keep rpms down. put the car into manual mode, and you'll see that you are in 5th gear waaaaaay before you it should be.

dont forget colder temps = colder fluid = its thicker, longer.

[phmichel]

Right you are my friend. It's not ambient air temp, it's CVT fluid temp. Per FSM:

" DTC/CIRCUIT DIAGNOSIS > [CVT: RE0F10A] P0740 TORQUE CONVERTER
• The torque converter clutch solenoid valve is activated by the TCM in response to signals sent from the vehicle
speed and accelerator pedal position sensors. Lock-up piston operation will then be controlled.
• Lock-up operation, however, is prohibited when CVT fluid temperature is too low.
• When the accelerator pedal is depressed (less than 2.0/8) in lock-up condition, the engine speed should not
change abruptly. If there is a big jump in engine speed, there is no lock-up."