2012 tundra won't start below 20 degrees.

My Tundra cranks fine but won't start below 20 Degrees. It roars to life but immediately dies. I have found that when I open the passenger door and blow a torpedo heater into the interior, it starts and runs fine after about 5 minutes.
What is in the interior or under the dash that would cause this? We have had a cold winter this year and I have successfully done this 5 times now to make it run.

 

Just noticed that on my 2011 Tundra , that there are 2 engine temp gauges. On on the left of the dash and another on the right side. I don't understand why they would put 2 in there and don't
know if that has anything to do with your problems. Does your ride have the 2 different temp gauges? If so do they give out the same readings that mine do when traveling and the engine is up
to temp. If they do show the same, then there is no correlation, but if they show different readings there might possibly be a correlation and one of them might need replacing.

 

They are both temp gauges, but they are not both for the engine. The left one is for transmission fluid temperature. Right one is engine coolant temperature.

 

The ecu is on the firewall behind the glove box and blower motor . Likely a solder joint on the board is separating fron contraction in severe cold. Pushing heat under the passenger dash would go directly to rhe ecu and warm it up quickly.

 

Sounds like you got the Sahara model.



JK the main truck ECU is behind the glove box. I am not sure why heating it would help. There are several data tables in the ECU that depend on the air temp and other temps to determine what amount of air/fuel/timing/rpm etc to do. The colder the more is added usually. Are you getting any codes when it dies like that? Coming to life then dying is common when replacing the battery or any time the battery is disconnected because the fuel trims are reset and other learned values, which to me means your truck is not adding the right fuel/etc or thinks its warmer than it really is etc. may make sense to disconnect your battery for 15 mins to force a reset.

 

Thank you for replying. Their are no codes and yes when it acts the exact same way when you replace the battery. Potentially could be as lr172 said above, "ecu... Likely a solder joint on the board is separating..." Yes, I tried disconnecting the battery and doing the reset. Made no difference.

 

This is a definite possibility. I had not looked yet as to where the ecu was or what was under the dash. It certainly seems related to expansion and contraction or a temperature sensor relaying wrong info.

 

There are no temp sensors in the cab that are critical to starting or running the engine. Those sensors and their wiring is all forward of the firewall. As you see in the pic above, the ecu is bolted to the firewall and the wires all come out on the engine side.