Water Thermosensor?
 

Hey guys,
I finally had a chance to pull that code that was causing the CE light to come on. Turns out to be code #9, the water thermosensor. I have no idea what this does, or what it measures, if it is broken or the connection is bad, if it is important, if I should be worried, or even how to find it. Anyone want to help fill me in? I really don't want to see that CE light come on all the time - it scares me. Let me know, if you can...

Thanks

Tyler

It tells the ecu to adjust for a cold motor , air / fuel ratio and timing , other controls. Just get it tested and replaced or find a broken wire or connector ect. Most chance it is the sensor that needs replacing . Do it and go for a ride and do not worry that you had to spent the money .

Where can I find this little thing, and how much would a new one cost? Does it become obsolete when the car gets heated up?

my water thermo sensor went out, and a few days later it would barely run.....replace it.....the sensor is a 2 wire connector and is easy to replace.....it only costs 40-50 bucks....

Could someone please tell me the specific area to look for it? I mean, is it close to the airbox, y-pipe, intake manifold, intercooler, battery, or what? I think I know where it is, and it looks as if the dealership broke it (wires pulled out, wire cut) and taped back together. If it is that, I can get it for free, and add one more thing to my evidence list. Thanks

If I'm not mistaken its the black thing in the pic with the wire coming off of it, its below the aftermarket sensor I put on, on the thermostat housing. Its a bad pic I know, sorry about that. Hope that helps.

That's awesome - thanks. I know exactly where that is. I have no idea why it's acting up, but at least I know where it is. One step at a time. Thanks again.

Tyler

i think the thermosensor is actually behind the filler neck.
under the little crossover pipe bracket.

The thermosensor is DEFINATELY behind the filler neck. Pull your crossover tube (black plastic pipe from turbo to intercooler) and look down the backside of the filler neck. There is a green connector attached to a brass colored sensor screwed into the filler neck backside, right underneath the coolant hose that leads to the pipe that runs to the throttle body. These actually seem to be failure prone due to heat.

Part No. F202-18-840A

Great! Thanks for all your help, guys - I'll look at it as soon as I can.

:) Tyler

many people replace it with a miata thermosensor to have the fans come on earlier.

Ummmm... thermoSENSOR tells ECU what temp the engine is.

thermoSWITCH (sits right below the thermosensor) switches the fans on at 224F, and is the subject of the Miata mod.

both are a pain in the ass to get at and repop :)

oops! :)

Oops, guess I was wrong, sorry man. Then whats that black thing I was talking about?

That bees the low coolant sensor. Erstwhile known as the "replace engine sensor" :)

you can get thetemp thermo sensor at advance auto parts for $21.99
and the fan thermo switch at napa for $12.99

I replaced the fan switch, and ended up breaking the thermoswitch in half, went down to advance just to see if they had it and they did.

I have learned to always check your local parts stores before just assuming that is a dealer only part.

OK, so if I pulled a code 9, which one of these sensors is acting up? Which one should I replace?

ThermoSENSOR, the one with the green connector, the upper sensor on the rear of the thermostat/water pump housing, give code 9, according to the manual.

so you can get the black one w/ the wireat any parts stores?

So this thermosensor is basically universal? I mean, if I go into Advanced Auto Parts and say "yeah, I need a water thermosensor for an RX-7" they would have it in stock? I have to get that thing replaced...I hate having the CEL come on - I feel like I am going to shit myself everytime it does

ok so the two wire is the thermosensor and the other one just under with only one wire is the thermo switch, is that it?

i don't have the connector anymore for the thermoswitch, anyone has a great idea? How come are there no thermoswitch on the japense engines? (i compared)

puma, that's right. The two wire is sensor, the single wire is switch.

Seems to me you might want to just do the Dysnay fan mod. Then thermoswitch is irellevant if you watch your temp gauge (linearized or aftermarket, that is...).

you can get it at any auto parts store the KEM part# is140-715 ask for that # and that is what you need. it should run for about $25.00, at least thats the price i sell it for in puerto rico.

that is for what? the switch? anyone know where i can get a connector for it?