2002 ZTEC 2.0 DOHC. At what CHT temperature increasing does the PCM change to closed loop control? And at what CHT temp decreasing does it drop out? I put in a new thermostate housing and noticed the dash engine temp gage is really low for most of my 50 mile commute in the morning. I put the scanner on this morning and stayed at ~170 degrees until I was cruising at 70mph for 5 minutes and finally saw 199F. The housing came with a thermostate already in the housing.