[vintagetrks]

I just put a 190 degree thermostat in my 06 LJ and now I have a check engine light. How do I get the check engine light to go out? I realize that the computer is probably set for a 210 degree thermostat but I would really like my engine to run cooler on the trails. I would'nt have thought a 190 degree thermostat would have caused the check engine light to come on. Any advice would be greatly appreciated.

[Unlimited04]

why don't you pull the code and see what it says?

[06rubikon]

Originally Posted by Unlimited04

why don't you pull the code and see what it says?

x2

[vintagetrks]

It gives me a code of P0118

[Knuckelhead]

Did you plug the temperature sending unit back in?

The OEM thermostat is 195 degree...

[the_great_white]

Originally Posted by vintagetrks

It gives me a code of P0118

Engine Coolant temperature circuit, high input

whatever that means....

[vintagetrks]

Yes I plugged the temp sensor back in and looked at my stock thermostat and it was a 195 degree unit. I don't know why five degrees would cause the check engine light to come on but it is. Scratching my head. Damned computer controlled stuff.

[joe108]

If you want to save your converter I would put in a 195 thermostat, if it runs too cool, it (computer)will think its cold outside and make the engine run rich, killing your cat...ask me how I know

[TJJP77]

A circuit high fault can be caused by the following things according to the FSM:

• ECT sensor voltage above 4.96 volts
• Faulty ECT sensor
• ECT signal shorted to battery voltage
• ECT signal circuit open
• Sensor ground circuit open
• Faulty PCM

If the thermostat caused the code, I would expect a P0125 or P0128. Having said that, you should put the correct temperature thermostat in the vehicle for it to run properly and go into closed-loop operation as quickly as possible.

I would carefully check the connector at the Engine Coolant Temperature sensor - you may have a bent pin, a pushed out terminal, debris/crud in the connector causing poor contact, etc.

[Jerry Bransford]

There is no such thing as a 210 degree thermostat for the TJ. It just runs at 210 due to the engine design but the actual factory specified thermostat is 195 degrees.

You can reset your CEL by disconnecting the right-most connector to your PCM, the one closest to the engine for 2 minutes and then reconnecting it. Make sure it clicks back into position. That saves having to disconnect the battery and losing your clock and radio presets.

[erockz]

Did you happen to start the jeep with the temp sensor unplugged? Even just for a short period of time, it would cause the code to set.

[Unlimited04]

Originally Posted by Jerry Bransford

There is no such thing as a 210 degree thermostat for the TJ.

you can get 205° thermostats....

look up STANT Part # 13352