2002 3.0 manual trans

The issue is once the car reaches normal operating temperature both radiator fans are running at full speed until I turn the ignition off. It is extremely loud. I have no overheating issues and coolant is topped off. I have tried a forum search but all I can find is info about one or both fans not working, the fans continuing to run after ignition is turned off, or the fans always being on (before reaching normal operating Temp). Reading other posts, I have noticed that the Fan Module is problematic. Would the module be the likely cause, or are their other potential causes to this problem? Any help with troubleshooting would be much appreciated.

 

IF, you have A/C or "automatic" mode selected (& it's warm outside w/temp set lower in cabin), BOTH FANS RUN AT FULL SPEED REGARDLESS OF CAR OPERATING TEMPERATURE. Same with cold outside, set warm in the cabin (automatic), the A/C compressor cycles to keep humidity out of the warm cabin air. This has been asked and answered innumerable times in this forum by doing a simple search.

IF the fans run after turning OFF key, this is a symptom of the car is overheating. Usually caused by bad thermostat, low coolant, coolant leak/loss.

 

I am not running AC nor is the Automatic Climate activated.

 

You mentioned with AC or Auto the fans run at full speed regardless of engine temp. My fans are only running at full speed once the engine is warm and at it's normal operating temperature.

And no, I am not having overheating issues, the fans shut off once I turn ignition off. It has never continued running after shutting off the car.

 

You have most likely one of two conditions. First it is possible the fan control module has gone out. It is also possible that the engine temperature sensor has failed and not reading correctly. A new sensor can be ordered for around $15.00 and might be worth swapping out before going to the more expensive proposition of the fan control module.

 

I'm with Avern. If A/C or automatic not on and fans run at full speed, the ECU is getting info to turn fans (both) on at full speed instead of "stepped" speeds. In simple terms (still could be sticking thermostat), the ECU is being told car needs maximum cooling effect from fans. It turns them on full because thermostat is allowing the car to get too hot for the load being pulled. Or the engine temperature sensor is malfunctioning reading incorrect high temperature again signalling the ECU to run fans at full. Lastly, the fan control module.

As Avern says, start with the least expensive and go up from there.

 

I doubt the thermostat is the problem. I say this because I started noticing this a couple of months ago, say when I'd pull into a drive through, that the fans were on full blast. It was something I noted, but didn't really give it much afterthought. It was only after noticing the same thing a few more times that I have paid more attention to it and have noticed that it runs full blast in the conditions I've described. I have been up to my cottage half a dozen times since then, which entails a 250km drive, there and back, and have had zero issues with overheating. Could the thermostat be sticking just enough to cause this fan problem yet not cause overheating?

I am also curious if there would be other noticable symptoms if it is indeed the ETS that is faulty.

I will most likely swap out the ETS with a new one, I know the module is expensive and hope it is not that.

 

Most likely not the ECM. Yes, your car can be hot enough to look (on the "gauge") to be in the "normal" range but enough to call for additional cooling. That "gauge" actually reads in the normal range for a fairly wide temperature range. It doesn't really reflect the varying degrees, just when "out of range" does it move significantly. For instance on my latest border run to buy lotto, I plugged in my OBD and once up to temperature the gauge never moved a micron. Yet reading the results the temp was from 175° F to 209° F traveling 150 miles round trip, level, climbing mountain pass, coasting down pass, etc.

 

Below is the info from the tech manual for the fan operation. Dell is correct in that you could be running HOT but not overheating. The overheating warning does not activate until you reach 120c.


Two variable speed electric cooling fans are housed in the cooling fan shroud for the cooling of the radiator. The speed of the electric
cooling fans are adjusted by the cooling fan motor control module, which is controlled by the engine control module (ECM).
The ECM determines the cooling fan speed by receiving inputs from the engine coolant temperature (ECT) sensor and the dual automatic
temperature control module (DATC). The ECM sends a variable pulse width modulated (PWM) signal to the fan motor control module to
operate the cooling fans at the required speed. The cooling fans are operated at slow speed when the engine coolant temperature is at
95°C (203°F) and are operated at full speed when the engine coolant temperature is at 105°C (221°F). A coolant temperature between
these temperatures will cause the cooling fans to be operated at a speed which is proportional to the engine coolant temperature.
When the engine is running with the ECT above 100°C (212°F), if the ignition switch is turned to the OFF position the cooling fans will
continue to operate for a time which is determined by the ECM.
If the PWM signal from the ECM to the cooling fan control module is between 7% and 95% the cooling fan control module will operate the
cooling fans at the required speed. If the PWM signal from the ECM to the cooling fan control module is below 3% and above 95% the
cooling fan control module will operate the cooling fans at maximum speed. If the PWM signal from the ECM to the cooling fan control
module is between 3% and 7% the cooling fans will not be operated.

 

Just had to run an errand, and I decided to see what the Self Diagnosis feature had to say about the engine temp sensor. (Is this feature accurate, or would I better off with an OBDII like Dell did in his previous post?)

I started the car in the self diagnosis mode and went for a 30 minute drive. I did some slow town driving and brought it to the back roads to give it some typical highway speeds. Once the temp gauge hit it's middle position the temp in the diagnostic mode fluctuated between 97.3 C and 102.3 C, which is within the range Avern stated. When I got back to my place, I decided to see if the Fan speed modulates with the temp while I am idling, and to my surprise it did. The fan still seems very loud to me though, I don't recall it being this noticable when I first purchased the car two years ago. I have put 19,000km on the car since I bought it so I'd like to think I am relatively familiar with it's day to day sounds, but I am starting to have my doubts now, hah. When I have time this week I am going to take a look at the two fans to see if anything physical could be causing my perceived loudness. I am also going to borrow a scanner from a friend to confirm the temperatures that the self diagnostic is giving me. Appreciate the advice and info, Dell and Avern.