P0402 Related To Bad Thermostat?

[turtle313]

My X has ran cold ever since I bought. I assumed it was a bad thermostat and went ahead and replaced it tonight. I've also been getting the P0402 code intermittently. I've read the other threads on here about it and it seems the DPFE is usually to blame for this. But, in my case, could it have been the computer trying to compensate for the engine always running cold?

 

[Eneurb]

The thermostat won't cause that code. There is about a 99.99999% chance you have a bad DPFE.

 

[turtle313]

I know the thermostat won't cause the code. I thought I maybe there was actually excessive flow due to the computer over compensatingor something. Just a thought. Anyway, about how much is the DPFE and is it usually available at Autozone?

 

[gss]

I just checked on the price of one her in WA at NAPA and it was around $60.00. The dealers want $100+change. I still haven't gotten around to change mine because of all the nasty cold weather.
I also run on the cold side of the temp guage but has plenty of heat and the previous owner had the thermostat changed a couple years ago.