Hard Start 2002 Lexus ES300 engine temp says it 169 degrees cold on 30 degree da

Unplugging each sensor while watching the ECT PID should identify which sensor is which.

Look for another coolant temp. sensor on the engine block, -head or close to the thermostat housing. The ECM coolant temp. sensor for the engine, will not be the same as, the fuel temp sensor.

That sounds like a two wire Engine Coolant Temperature sensor to me. The hard start symptoms you're describing make sense given that the sensor signal is skewed high. Cold air is denser and requires a proportional amount of fuel for combustion, and it definitely sounds like your Lexus is starving for fuel when cold. :silly:

With the sensor unplugged, key on engine off, measure voltage on both wires. Should be 5.0V and 0V. Then short the two wires together and recheck for voltage. Should be 0V. You can also look at your temperature PID again - should be 250 degrees or higher. If those tests pass, you're good to install a new ECT.

Minor wrote: I need to start making videos of this stuff for you guys. if it's weird or off the wall it seems to end up at my place because no one can figure it out or they won't time the time too. So, they try and throw parts at the problem hoping they fixed it.

You're definitely in the right forum. :lol:

Case in point, I had an '08 Wrangler come to me after other techs had tried to fix repeated overheating and thermostat codes. Coolant had leaked through the ECT into the connector, causing the ECT signal to max out at 150 degrees. :silly: Naturally, the PCM flagged a failed thermostat. It also never saw the engine overheating at idle, and thus never turned the fans on. Oops!