The trouble began by my van not shifting out of 2nd care... van had gone into limp mode. Shortly there after, the engine light came on and my van started to overheat. We ran the codes and got PO720, PO731, and PO0500. Thought it was the speed sensor. Anyway, shifting problem went away, but overheating problem stayed. My husband changed the thermostat. NOW... we are still overheating... smelling maple syrup and I don't seem to notice the shifting problem anymore. I am having problems when it is warm outside and I am running the air. HELP!! I know that overheating and limp mode can be related, but does anyone think I have two problems or just one??? Also, we cannot find a leak either!!! HELP

Any dash warning lights on? Usually when the computer commands a "limp in" mode it turns on a warning light and sets a trouble code int he computer.

P0131 and P0137 - OBD-II Trouble Codes - RepairPal

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Definition of error code P0131 and P0137 - 02 Sensor Low Voltage (Bank I ... Decrease in fuel Eeconomy because PCM is in a "limp home" mode; Engine dies .... The AAmco company replaced 2 oxygen sensors in my car and the engine light ...

Sounds like trans has a major problem and has gone into "limp mode". Actually goes into 2nd gear and will not go into any other forward gear. This is to keep you from being totally stranded. Get it checked.

the .pcm puts it in limp mode and it will stay in mode until light is turned off. You need to get the trouble code, repair it, erase the codes (with a scanner that retrieves the codes), and then you will be out of limp home mode.

Ah, I see. You want to outsmart the computer? Right logic, wrong computer. I think the problem is not in the transmission, but it is the engine computer that has communicated with the transmission computer and put the car in limp-in mode. The fix engine light is sent from the engine computer, and this is the main computer in the car, the main drive train computer, if you will.
The short answer is yes it will reset, by just unhooking the battery. Won't do any harm. Start it up about an hour later, and be sure and let it warm up to normal operating temperature (closed loop) before you take it out for a test drive. Otherwise you may be miles from home in 2nd gear limp-in mode again.
The real fix is to talk to your car...like communicate with the computer and get those trouble codes read...talk to it nice, not the abrupt tone of the glaring idiot light, and maybe it will respond in a kinder, gentler easy to fix diagnostic code!!!!
Good luck.

did you have pinion factor and quick learn performed on the trans module after replacement? if not then the trans won't shift correctly. also is the check engine light on with any engine codes in memory? the engine module may the trans stuck in limp-in mode(2nd gear).

it sounds like the transmission has gone into what they call limp in mode which indicates a problem with the transmission.you will have to have a scan tool put on it to pull the code out of the tcm(transmission control module) which will turn on the engine light.at the same time it may show a code for the temp control.

The EMC detected and problem so it's in limp mode, As long as it's in limp mode the 4th and OD will not activate. Take care not to burn up the transmission by running it hard while your in the limp mode.
Your going to have to get the truck scanned to clear any codes and why there are DTC codes. Auto Zone scan for free and most auto shops charge $10.00 to $20.00 to scan sine they want the business.
If you want to clear the codes your self you can put the ignition to the run position and pull the ECM (Batt) fuse out for 20 sec and place it back in then start the truck. It may stall but let it, just start it again and this would have cleared all the DTC code history.
The transmission should be running fine unless there is a problem and the service engine light will be on again and you'll be in limp mode still with an updated DTC in the ECM.
Good luck and hope this helps.

Transmission has gone into "limp" mode. Have it scanned soon.

When the trans. sticks itself in 2nd gear and stays there is because it's detecting a trans. problem and puts itself in "limp in" mode. When it happens again, to somewhere to have a scan done on the trans. so you can find out which sensor on the trans. is acting up.