ISFFUN

iTrader: (4)

I'm on a strange path with this mystery.

Under the lower intake runner, there are two coolant related (supposedly) sensors. The front/first one is the 2-wire green coolant temperature sensor (?) and the second appears to be the gauge sender unit. But why is that thing also referred to as a cold start switch for the EGR?

The parts catalog shows a cold start injector p/n 89462-20020.

Searching that links to a cold start switch on Google. Looking on Amazon takes you to a EGR timer switch for managing the actual temperature data for the ECU. e-Bay shows similar results.

An old post here shows a diagram without the second sensor and a user adds a comment that says the first green one is the gauge sensor, and the second grey one is the actual ECU sensor based on the idea that it's only one wire, but the connector is 2 wire, so something has changed.
https://www.clublexus.com/forums/per...-i6-sc300.html

The 1997 SC300 vol.1 repair manual shows ABSOLUTELY nothing about that sensor and I'm starting to think it was accidentally omitted or just a major typo. There is only one picture in the cylinder head section that says "ECT sender gauge"

Does anyone know which one is actually for the ECU and actually controls cold start and EGR function?

See image attachment for actual 1997 year FSM with sensor.

Reason I ask is that I'm having a freakishly amazing time trying to pass smog (high NOX, nearly everything has been tested and replaced including the entire head) and I thought I had replaced the ECT coolant sensor (a couple of times now) and actually just replaced the gauge sensor for the dash!

freakness

Dude,


The two-wire green plug is a coolant temperature sensor and is used by the engine computer. The single-wire grey sensor on the right is for the coolant temperature level in the dashboard display. That is how it is on my 1995 SC300.



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