Help!!! P0117 & P1493

[GSTurbo05]

I was going to work on thursday and suddenly 2 blocks from my job my cars CEL comes on with the battery light, so im thinking its the battery or alternator. So i take it to Autozone and grab the code reader and it reads P0117 meaning the ECT sensor voltage is to low, Another code poped up aswell P1493 Bttery temperature sensor voltage to low
I replaced the ECT sensor and the code still pops up, Also my fans are driving me nuts they wont shut off, even when you cold start they start right up. I dont even know where the hell the battery temperature sensor is located, the guy at autozone said it my be affecting my ECT sensor if its not replaced. How am i supposed to raise the voltage???
Can anyone help me? has anyone had this problem before???

Just to mention its on a 1996 Eclipse RS

 

[GSTurbo05]

Ok heres the tests the right way with the key on.

Basically... I need to know:
What voltage you have at the sensor signal wire at the sensor connector? 5.14v
How much resistance to ground you have at the ground circuit wiring at the sensor connector? 7.77ohm
And finally how much resistance there is on each wire from the sensor to the PCM connector pins? on pin number 26 8.70ohms

You need more tests let me know, thx

 

[Doug99RS]

Ok heres the tests the right way with the key on.

Basically... I need to know:
What voltage you have at the sensor signal wire at the sensor connector? 5.14v

This is good. Most of the time we only see about 4.8 or 4.9 Volts.

How much resistance to ground you have at the ground circuit wiring at the sensor connector? 7.77ohm

There's too much resistance on the ground circuit.
Here's a link to help explain things a little dealing with Resistance and voltages and such.
http://www.the12volt.com/ohm/ohmslaw.asp
Bottom line is higher the resistance to ground the more inaccurate the sensor reading is going to be. You'll always want less than 1 ohm on any strand of wire.

And finally how much resistance there is on each wire from the sensor to the PCM connector pins? on pin number 26 8.70ohms

From the computer connector to the ECT connector there is 8.7 ohms of resistance? This would tell me that your problem is in the ground circuit wire between the two components. Verify this one last time just to make sure.

You need more tests let me know, thx

You'll need a test light for anything more than this. Also, humor me and check your meter leads. Touch them together and make sure your resistance is 0.00 ohms.
Doug

 

[GSTurbo05]

Alright so i touched both meter leads together and it read 0.00 on the meter. Correct me if im wrong but what i did to get the voltage on the PCM is i placed the black lead on the negative post of the battery and placed the red lead on pin 26 on the pcm, is that correct? i didnt know how to get a reading without doing it that way.

 

[GSTurbo05]

Alright redid the pcm test on pin 26 and yes it reads 8.70ohm's.

 

[Doug99RS]

Alright so i touched both meter leads together and it read 0.00 on the meter. Correct me if im wrong but what i did to get the voltage on the PCM is i placed the black lead on the negative post of the battery and placed the red lead on pin 26 on the pcm, is that correct? i didnt know how to get a reading without doing it that way.

That sounds like part of a step to confirm that 5 volts is getting to the ECT sensor. Basicalyl, you've checked for the 5 volts at the source. But now you need to do the same thing at the sensor connector itself. You had the negative lead of your meter in the correct spot. Just plug in the PCM connector and check for voltage at the sensor connector itself. You should have the same voltage (within a tenth or two) of what you had directly at the computer. Doing that will finish checking the 5 volt supply circuit.

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This is a diagram of another chrysler product with the same 2 wire ECT sensor. DO NOT PAY ANY ATTENTION TO THE COLORS OR THE PIN NUMBERS because they probably don't fit your car. BUT... what is important is thatyou have a picture of what I'm trying to explain. When I'm referring to pin numbers it's only in regards to the picture and not your car. So far it sounds like you've verified you've got 5 volts at this car's pin 26 in the C2 connector side OF THE COMPUTER. Next you need to plug the computer connector back in and go to pin B of the ECT sensor to make sure there is the same voltage. As you can see in this diagram there are no intermediate connectors, no splices and no other components between the computer and the sensor.

Pin A of this diagram is the ground circuit of the sensor. S117 is a splice, C111 is a connector, S110 is a splice in the fuse block under the hood (PDC), and then the wire finally ends up at the computer c1 connector pin 43. Yours is going to be pretty close to this. Each time is splices that means other sensor grounds share this circuit. Each connector is an opportunity for corrosion leading to high resistance. I don't beleive the 2gnt has any connectors between the engine harness and the PCM harness so you've probably got a section of wire that is bad or a bad ground for the computer.

On YOUR car, plug the PCM connector back in and check for 5 volts at the ECT sensor pin B. You should have 5 volts. If you don't then you've got high resistance in the wiring. You've already proved that the computer is putting out 5 volts AT the computer.

If you've got 5 volts at the sensor then you've got a ground issue.

Next you'll want to unplug the connector of the PCM that has the sensor ground circuit in it. Check resistance from pin A of the ECT connector to the sensor ground circuit pin in the PCM connector. You should have little to no resistance. If you DO have resistance then the problem is in the wiring. If you DON'T have resistance plug it back in at the computer and then go to battery negative with one lead and pin A of the ECT and check it again. If you find resistance to be back up to 7 or so ohms then the computer is not grounding the circuit properly.

If the computer isn't grounding properly you could have a bad computer OR you could have a poor ground somewhere on the car for the PCM itself.
Doug

 

[GSTurbo05]

Here use this, This is for the 2.0l non turbo eclipse :

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[GSTurbo05]

Ok heres the readings

PIN 26 on the computer : 0.54v
ECT plug PIN B reading : 5.17v

ECT plug PIN A to the ECT plug PIN A ground on the PCM : 0.03 OHMS
Battery Ground to ECT plug PIN A : 7.9 OHMS


Also i want to ask you, when you test OHMS i place the multimeter selector switch on 200 and if its for kilo OHMS i place it on 20k, correct?