maaaan, code 21 this is gettin old

[deftsound]

ok i replaced the wrong sensor, looks identical to the ect sensor though, but none the less the wrong one

 

[5.0Droptop]

Here is that picture again. I used photo chop to mark the sensors so you can be sure you have the correct one .

 

[jrichker]

Wrong sensor, guys, the sensor in the water passage is the temp gauge sender.

The ECT sensor screws into the heater tubing on the RH front of the engine. See http://www.veryuseful.com/mustang/tech/engine/images/mustangEngineHarness.gif for some clues.

May times guys will rip out the heater feed tubing because they don't have a heater or a coolant feed to the EGR. That's a big mistake, the ECT lives there and there isn't an easy place to relocate it.

 

[5.0Droptop]

I stand corrected. Doh! Sorry Deft. You did replace the correct sensor. You said you dont have a heater core are the old heater core lines connected together so it can flow?

 

[Daggar]

Wrong sensor, guys, the sensor in the water passage is the temp gauge sender.

The ECT sensor screws into the heater tubing on the RH front of the engine. See http://www.veryuseful.com/mustang/tech/engine/images/mustangEngineHarness.gif for some clues.

May times guys will rip out the heater feed tubing because they don't have a heater or a coolant feed to the EGR. That's a big mistake, the ECT lives there and there isn't an easy place to relocate it.

Yep... he's right. Behind the Dizzy just outboard of the passenger side fuel rail. Put me down for "D'oh!" as well.

Working from a memory like mine can be a dangerous thing.

 

[giddyup306]

A bad ECT sensor could cause your codes for running lean as well. It's what tells the computer whether the car is warmed up or not. Once the car is warmed up and the computer changes modes (to warmed up mode) the air intake temp sensor in combination with your 02 sensors determine your AF mixture. In other words... the ECT acts more as a "switch" for the computer than an actual sensor.

The only thing is that the comp will go into limp mode or failsafe mode and use the air temperature sensor and a predetermined value to guess what temperature of the coolant. The EEC can usually compensate for it being off. Also the computer going into "closed loop" is determined by 1 a predetermined amount of time must pass 2 the 02 sensor must put out a useable signal 3 certian temperature must be reached. It is not dependent on the ECT sensor. Also as I stated before the ECT sensor is a two wire sensor.

 

[deftsound]

damnit i just got done puttin it in the wrong spot

 

[giddyup306]

damnit i just got done puttin it in the wrong spot

It happens to the best of us. Did you ever see droptops title?

 

[5.0Droptop]

It happens to the best of us. Did you ever see droptops title?

Whats my title?

 

[giddyup306]

Whats my title?

I thought that was you. Must be wrong. There was someone here on the forums that posted under droptop... I don't remember what the full user name was. But his CT was "damn it why am I out of washer fluid again". He hooked up his washer hose to manifold vacuum.

 

[5.0Droptop]

haha I remember that. wasnt me tho.

 

[giddyup306]

Yeah that thread still gets brought up every once in a while.

 

[deftsound]

hhahah thats hilarious, man droptop you should see this ghetto rigged 2 liter bottle coolant overflow container... , ive been catchin so much **** around campus for it.


but im still getting code 21

 

[giddyup306]

hhahah thats hilarious, man droptop you should see this ghetto rigged 2 liter bottle coolant overflow container... , ive been catchin so much **** around campus for it.


but im still getting code 21

Did you check to see if the wiring is okay?

 

[Daggar]

The only thing is that the comp will go into limp mode or failsafe mode and use the air temperature sensor and a predetermined value to guess what temperature of the coolant. The EEC can usually compensate for it being off. Also the computer going into "closed loop" is determined by 1 a predetermined amount of time must pass 2 the 02 sensor must put out a useable signal 3 certian temperature must be reached. It is not dependent on the ECT sensor. Also as I stated before the ECT sensor is a two wire sensor.

The range of the ECT sensor is certainly a determining factor in what mode the computer enters into. Typically the low limit for the computer is 140* on the low side and around 190* (where it starts pulling out timing) on the high side. It's true that the EEC can make adjustmments but that is not for a sensor that is constantly out of range. The adjustments the EEC can make are for momentary spikes. With a sensor that is bad or constantly out of rage... the computer is not able to enter "warm" or closed loop mode which goes back to what I was trying to get across earlier and that is that the ECT "acts" as more of a "switch" than an actual sensor (a sensor being something that provides a constant stream of data for the computer to use to make on the fly adjustments).

 

[deftsound]

well im pretty sure the reason i got the code 21 is because i really was low on coolant and the coolant was consistantly staying at a hot temp. So whenever i get this new overflow canister i think it should pretty much fix my problem because it wont be leaking all over the ground anymore.

 

[5.0Droptop]

Deft and I were talking on aim and i asked if he had a overflow container. because he said he was losing coolant but wasnt certian where. he didnt have one so i told him to use a 2 liter bottle for now.

 

[Daggar]

If that doesn't help perhaps start looking for leaks around the MAP or maybe the MAP sensor itself? Computer may be seeing a rev up when there is none or maybe more rev than there is (referring to the lean code he got).

 

[jrichker]

Code 21 – ECT sensor out of range. Broken or damaged wiring, bad ECT sensor. Note that that if the outside air temp is below 50 degrees F that the test for the ECT can be in error.

The ACT & ECT have the same thermistor, so the table values are the same

ACT & ECT test data:

Use Pin 46 on the computer for ground for both ECT & ACT to get most accurate readings.

Pin 7 on the computer - ECT signal in. at 176 degrees F it should be .80 volts

Pin 25 on the computer - ACT signal in. at 50 degrees F it should be 3.5 volts. It is a good number if the ACT is mounted in the inlet airbox. If it is mounted in the lower intake manifold, the voltage readings will be lower because of the heat transfer.

Voltages may be measured across the ECT/ACT by probing the connector from the rear. Use care in doing it so that you don't damage the wiring or connector.

Here's the table :

68 degrees F = 3.02 v
86 degrees F = 2.62 v
104 degrees F = 2.16 v
122 degrees F = 1.72 v
140 degrees F = 1.35 v
158 degrees F = 1.04 v
176 degrees F = .80 v
194 degrees F = .61

Note that all resistance tests must be done with power off. Measuring resistance with a circuit powered on will give false readings and possibly damage the meter.

Ohms measures at the computer with the computer disconnected, or at the sensor with the sensor disconnected.
50 degrees F = 58.75 K ohms
68 degrees F = 37.30 K ohms
86 degrees F = 27.27 K ohms
104 degrees F = 16.15 K ohms
122 degrees F = 10.97 K ohms
140 degrees F = 7.60 K ohms
158 degrees F = 5.37 K ohms
176 degrees F = 3.84 K ohms
194 degrees F = 2.80 K ohms

 

[giddyup306]

The range of the ECT sensor is certainly a determining factor in what mode the computer enters into. Typically the low limit for the computer is 140* on the low side and around 190* (where it starts pulling out timing) on the high side. It's true that the EEC can make adjustmments but that is not for a sensor that is constantly out of range. The adjustments the EEC can make are for momentary spikes. With a sensor that is bad or constantly out of rage... the computer is not able to enter "warm" or closed loop mode which goes back to what I was trying to get across earlier and that is that the ECT "acts" as more of a "switch" than an actual sensor (a sensor being something that provides a constant stream of data for the computer to use to make on the fly adjustments).

I never said it wasn't. I said that a predetermined temperature must be met and implied that it used to ECT sensor to determine it. You made it sound as if it was the only factor. I'm merely stating that it is not.