I use both Freescan and Datamaster and noticed the engine temp reading does not match the coolant temperature gauge on the dash which always stays around the 2nd hash mark (I'm really not sure what temp the 2nd hash mark is suppose to be). Regardless, the datamaster/freescan readings are usually around 200-210*, the gauge appears to be much less than 210. I have the stock stat in the car. I thought maybe my coolant temp sensor was going bad or that our scanner programs are reading from a different sensor. Does anyone here care to enlighten me?

 

The second hash mark is about 190-200 degrees. It's not very accurate anyway, so I wouldn't worry about it. The computer gets temp readings from the sensor on the WP, which is also what the scantools read from.

 

Yah, and the gauge reads from the coolant temp sensor on the driver's side of the block. Different sensors, and it's likely that the temps are actually different too.

 

thanks guys, that's what I wanted to know.

 

yea, historically the guage cluster is not accurate, datamaster is what the PCM uses, to determine whether your in closed loop or open loop. I just had my car dyno tuned yesterday, between runs i was in open loop far too long. So I am going back up to the 180 thermo.