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jazzmaster, ASE Certified Tech
Category: Acura
Satisfied Customers: 2951
Experience:  ase certified--32 yrs experience
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I have a cl2.3 with a gh voltage temp sensor. scan tool is

Customer Question

i have a cl2.3 with a high voltage for the temp sensor. scan tool is reading -40. replacing the sensor didnt do the trick. what should i do to test the wiring? is there any common break points? and if it comes down to it and i wanted to cut the wires at the pcm/ecm and run new ones which ones would they be?
Submitted: 1 year ago.
Category: Acura
Expert:  K. Wiggins replied 1 year ago.

On the green and black wire you should have 5 volts with key one.

With the sensor and ECM disconnected you should have continuity on the wed and white wire that runs from ecm to coolant temp sensor.

I'll post the wiring diagram below. If you have any questions jsut reply back.

Customer: replied 1 year ago.

if i have a supply of 12v what should i assume the issue is

Expert:  jazzmaster replied 1 year ago.

h i, on the green/black ( gr/blk) wire with the connector disconnected ,what is the voltage reading at that wire with the key on ?

this same wire also, goes to the TPS sensor,the o2 sensors,the iat sensor and the egr .

see if the voltage reading is the same at each sensor.

It should read 5 volts .you may have to disconnect each sensor .

if the reading is still 12 volts ,this could be a shorted o2 sensor.

what I would do is this

disconnect the coolant sensor/egr/tps and iat sensors then see what the voltage reading is on the gr/blk wire

if it is still 12 volts then disconnect the o2 sensors one at a time and see what you have then .

if then the voltage goes to 5 volts then one of the o2 sensors is bad .

what kind of scanner are you using ?......jazzmaster ..

Expert:  jazzmaster replied 1 year ago.

hi, do you still need assistance and have you checked anything I mentioned ?

Customer: replied 1 year ago.

Where is the Iat sensor? It is reading on my scanner correctly. With everything disconnected I have 12 volts at my temp sensors still (2 separate sensors correct?) everything else reads correctly 4.9v signal

Expert:  jazzmaster replied 1 year ago.

I wouldn't worry about the iat sensor but that should be on the air box or hose from it ..

at the tps sensor connector do you have bat voltage on the yellow/blue wire and at the coolant sensor the red/white wire with those disconnected ..

also, what is the make and model of the scanner you are using ?

Customer: replied 1 year ago.
Ok let me back track a few steps, there is seemingly 3 temp sensors with the same connector, on by the thermostat, one under the dist, and one just to the rear of those? And it's an otc9450 which one is telling the scanner there is an issue? I checked the one under the distributor and found no signal at all, the front and rear ones have 12v supply
Expert:  jazzmaster replied 1 year ago.

the one near the thermostat will be the one ,and is that the one you replaced ?

Customer: replied 1 year ago.
Center is new
Customer: replied 1 year ago.
what is the point of there being three of them and are all supposed to have a 5 V signal ?
Expert:  jazzmaster replied 1 year ago.

the coolant sensor is the one that will tell the pcm and the scanner the temp that you are seeing ..

the is a red/white and a green/black wires at the connector .on the red/white will be 5 volts and the green/black is a ground

Customer: replied 1 year ago.
Ok that's the one I'll check, maybe Jump a 5v source to it and see what happens, also the other two are correct at 12v then?
Expert:  jazzmaster replied 1 year ago.

oops sorry the green /black is the 5 volt reference signal wire the red/white goes to the pcm

you can jumper those wires and see if the scanner shows the temp different .

sorry about that ..

if you don't have 5 volts on the green/blc wire with the key on then there is a break in that wire .

the egr and throttle position sensor should also, show 5 volts ,so if you have that at the egr and tps sensors then definately there is a break in that wire and you will have to trace that from the coolant sensor connector back through the wiring .

look for a pinched wiring harness or checwed wiring ,anything that looks out of place or not normal i n the harness ..jazzmaster ..

Customer: replied 1 year ago.
to test the sensors can I do a continuity test or is there an ohm amount I should look for
Expert:  jazzmaster replied 1 year ago.

the resistance is checked as per the temperature of the sensor or coolant .