Code 69, May be a nice number but its buggin me!

[94mx3precidia]

So i have code 69, coolant temp sensor. So far ive replaced both sensor and sender with new parts. I chose the temp sensor from a 94 probe gt. There were 2 options for the temp sensor, if the car was auto or manual. So i baught both, the one for the manual car didnt fit into the pigtail for the sensor (looked identical) but the one for auto did. So i figured that the klze did come with a auto tranny so i stuck with that one. So with both sensor and sender replaced i reset the ecu and its still throwing code 69 and the idle is high and the rad fan is on too much. Whats wierd is that the sensor that i have in there now is the same sensor as the ford probe gt. Should i be going with a different car or should the sensor for the prbe gt be okay?

Now the sensor for the probe gt manual car was different so im thinking that the one i need. Looks like i might have to buy the pigtail as well.

[Dan [Sac]]

What year is the computer in the car? Are your fans on all the time?
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Check the sensor itself

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Here is some info from the Malfunction FAQ:

Code 69: ECTF Sensor

Relay Purpose:

The ECTF (engine coolant temperature - fan) sensor is used by the PCM in 1993 models to determine when it is necessary to turn on the radiator cooling fans. In 1994, the ECT (see code 9) was used to make the same determination, saving the expense of one sensor and its wiring.

Fault Description:

The PCM will set a code 69 if the voltage on the ECTF sensor circuit falls below 1.15V or rises above 4.98V.

NOTE: This code and sensor is present on 1993 model year PGTs and V6 MX6s only. Model years 1994 & 1995 will not report this code.

PCME Fault Control Moding:

To safeguard against overheating, the PCME will activate the cooling fan constantly when code 69 is present.

Memorization:

This code is memorized in the PCME non-volatile memory.

Things To Check When Diagnosing:

1. Check the sensor plug. Make sure there's no corrosion and that the wiring is in good shape.

2. Use the table for code 9 and check the resistance of the sensor. They should be similar.

3. Replace the sensor if necessary.

[94mx3precidia]

okay so the ecu is from my 94 mx3. Now can a 94 mx3 also be throwing the ectf error? beacause im for sure throwing a code 69. My fans arnt on all the time, its just when my enine warms up to normal operating temp they turn on but dont turn off. Does the klze engine run hotter than the k8 engine? Is it the sensor that shuts the fan off or is it the relay that shuts the fan off?

[nvidian]

Hi,
I have almost similar problem. I have a 93 mx3. I recently installed new K8 engine(old one broke down) from a garage in toronto. Myt problem is tht moment i turn on my car rad fan starts n never stops. Its also idling at 1100 rpm it never goes down that. I pulled engine code which was 69 coolant temp sensor. I am taking it back to the garage I was wondering if any one could give me heades up wht can it be.
thanks

[Whisper]

Ok, here's how it works (temp gauge sender is not included in any of these descriptions).

Pre-94 models: Two sensors. First temp sensor determines when the fan needs to turn on. Second one determines when the fan needs to turn off. Both sensors send the information to the ECU and ECU triggers the fan relay.

94 and later models: Just one sensor, determines whether or not the fan needs to be on, sends signal to ECU and ECU triggers the fan relay.

I'm aware of the following problems:

a) You have earlier year ECU and don't have enough sensors on your motor (later model motor). ECU can't find all the sensors it's looking for, switches to emergency mode and runs the fans all the time. Pretty sure the car has to warm up to operational temperature before the fans kick in, and then they won't turn off.

b) Your later model ECU is chipped with an EPROM designed for the earlier year models (like a Probinator). ECU doesn't have the harness for the second sensor, but the chip looks for both sensors anyway, finds only one, freaks out, continuously runs the fans after warm up.

c) You have the wrong sensor(s). Pretty sure the single sensor set up uses a different sensor than the dual sensor set up. I don't know when Probe came with a single sensor set up, so I can't comment on that. Get the correct MX-3 sensor that is appropriate for your set-up and your ECU.

d) Sensor is just simply bad (unlikely, but possible).

What's the number on the ECU that you have right now?

[94mx3precidia]

okay, so what would be the answer to option b? Because thats my case and i still havnt been able to figure it out.

[solo_ryder]

Dan that is good info.

He/She proly has a k834 ecu, like what I had in my car.

I ended up swapping over a 92 harness with the extra coolant sensor. However, now i am running into code 67 which is a relay for the coolant fan..

Either way, she proly has a chipped ecu that cannot recognize the extra sensor (since its not there) and runs like fan like mentioned above. The way to fix that is to do what I did above, or maybe try a kl31/36 ecu.

[hgallegos915]

I got rid of the code by just connecting the sensor to the harness. It not even in the engine. just hanging around there.

[94mx3precidia]

I got rid of the code by just connecting the sensor to the harness. It not even in the engine. just hanging around there.

How did you connect the sensor to the harness? did you just splice in an extra connector or something?

[Whisper]

I don't think there's really a way to fix problem b). I have the same issue, it's a pain in the butt. I've looked into many different approaches and finally ended up just wiring fans to manual switches, so I can shut them off when they don't need to be running, to keep them from burning out. I guess you could swap in an older harness, but then you might run into different problems.

[nvidian]

Thanks whisper for the prompt reply. I think its a). I checked the motor its year 95 and only has one heat sensor. My Old motor was 93. So i think I have a 93 ecu and 95 motor. Will swapping ECU's solve the problem? Also are there any other side affects of runing 95 motor with 93 ECU . I am takin car to garage tomorow.
Thanks

[Whisper]

So do you have a spare harness plug from the second sensor just dangling? If so, you could get the coolant neck from a 93 and swap it on. Or tap the coolant neck you have on right now, put the second sensor in and hook it up.

I don't know if 95 ECU would be OBDII or not (I think it's only 96 and up), and what type of issues that would cause, but you can definitely try. A valid option.

[94mx3precidia]

So i guess the only thing to do to stop it from running in limp mode is to get myself a kl31 or 36 ecu. Too bad i wont have a check engine light....

[Whisper]

Well, it doesn't run in limp mode now. It's just running the fans. Of course if you switch to the original ECU/EPROM, then it probably will run in limp mode. So yeah, a ZE ECU might work. Make sure it's from the right year, too. Else it'll still look for the extra sensor.

[solo_ryder]

So i guess the only thing to do to stop it from running in limp mode is to get myself a kl31 or 36 ecu. Too bad i wont have a check engine light....

As whisper said above. If you have a 93 harness and a 95 motor, there will be a extra coolant wire hanging on the harness (black plug). All you need to do is tap the coolant neck and put in the coolant sensor from your old motor and that will fix the problem. You can also swap the coolant neck.