What causes the trans to go to hot shift mode? My trans started doing this. Somtimes it will be in normal shift and just go to hot shift for no reason. I think it might have a bad pressure switch. What all does the pressure switch control? I know the trans is not hot.

 

Can someone help me out here?

 

I dont think thats and issue if you are just watching the scanner, My understanding is the trans has three difference settings in the PCM that are used and they are COLD,WARM and HOT modes, They are all normal modes just the tables for shift and presure ajust for each state.

 

looking with hp tuners there are three different modes normal, performance, and hot. That is under full throttle shift speed and rpm. Performance mode is only used on vechiles with a tow / haul button. When i scan my car sometimes it will go into hot mode. When this happens the car shifts way to fast and the converter locks and unlocks crazy. There is not pattern to when this happens. Sometimes when I first start the car in will be in hot mode even when its cold. I;m not sure what controls this? I think it might be in the pressure control switch.

 

You may want to try changing the presure manifold switch the temp sensor may be bad in it

 

Once the transmission temperature goes over 265 degrees the PCM will use hot transmission strategies.
I would check the TF temp sender if your transmission is going into hot mode when it is cold.

 

I set that to the max degrees to try to lock out hot mode and it still goes into it. I ordered a new presure manifold switch. That should fix it.

 

I put the new pressure manifold switch on and still does the same thing. I'm going to check hte wiring now. Is there anything else that could cause this?

 

Have you checked to see what the actual temp of the unit is when it switches to the hot mode?

Point is, it could actually be overheating. Be sure to check the cooler flow. If you have replaced the Manifold Switch then it is time to verify that the harness has not been compromised.

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Yes it's not overheating. i can get in it when its cold and start it and it will be in hot shift.

 

I would get the presure manifold switch as replace , The temp sending unit is in there and may be faulty

 

I replaced it with a new one and it does the same thing.

 

Hmm can you watch the scanner to see what the temp reading from the trans actually is?

 

Yeah i can see the temp. The other day the car had been sitting for 4 hours started it up turned on the scanner and hot shift and 300 degs. im going to start checking wires.

 

I would start checking wires as you said sounds like you have a open or short to ground somehwhere.