🤮🤮🤮🤮

 

Hello. I’m very sorry for resurrecting an old thread, but I’m really at a loss. TLDR summary at the bottom.

I haven’t used my x type since May of last year. I’ve gone through 5 FCM modules, but still not working properly until now. Now, I’m no longer sure if it is the FCM or a sensor feeding wrong data into the ECU/FCM.

First problem we noticed that started all of this was that one of the two fans stopped working, which made the coolant temp gauge needle move a bit higher than normal. Eventually diagnosed by the mechanic to be the FCM. This is where my problem started.

1. First FCM - I bought the chepest one I could find online. Took a gamble and thought I could get lucky with an easy/cheap fix. Ended up making the fans go at full speed once connected, even without the key in the ignition.
2. 2nd FCM - did a little bit of research but still wasn’t willing to spend on the OEM FCM. I bought the Beck & Arnley (203-0291). Heard some good reviews about this. Installed it and thought that was it. Brought it to the mechanic to have my AC fixed. While they were testing their work, they told me that the radiator just suddenly exploded. Turns out, the fans just stopped working.
3. 3rd FCM - returned the FCM and waited for a replacement (same B & A 203-0291). Installed it and it worked perfectly just like the previous one. It even varied the speed of the fans, low to high, when needed. Upon monitoring, when the engine gets to normal operating temp (around 95 C /203F), both fans just spin at low speed. This causes the coolant temp to rise very slowly. Since I don’t want anything to explode like before, I turn off the engine at this point. When I go on and try to start the engine, I noticed that both fans just don’t work. When I wait the next day, whenthe engine is cold again, the fans suddenly work perfectly fine, changing speeds until the engine gets hot again. Then they stay at low and stop when you turn the engine off and on again.
4. 4th FCM - Thought I’d finally invest in the OEM module to make these problems go away. Bought the Gates FCM 134. Installed and totally didn’t work - dead. Returned and asked for a replacement.
5. 5th FCM - same, Gates FCM 134. Showed the same behavior as the Beck & Arnley’s. Only difference is that with this module, the fans stop working at a higher coolant temp. Fans still work if I restart the engine below 100C / 212F.

I live in the Philippines. This is why it is taking this long. The purchase/return shipping took a lot of time and unnecessary shipping costs.



TLDR:

OEM FCM still showing same symptoms as previously bought FCMs.

Perfectly works when the engine is cold.

When engine gets to normal operating temp (95C / 203 F), fans stay at low speed.

Coolant temp gets higher. So I turn off engine.

When I try to start the engine again, both fans no longer work.

I have to wait for the next day when the engine is cold again.

Fans work properly, then eventually show the symptoms I just stated above.



Is it possible that it is not the FCM, but instead, a faulty sensor that feeds wrong data into the ECU/FCM? If so, which other sensors could these possibly be? (i just replaced the coolant temp sensor, still the same) it’s like the fans refuse to work when the engine is already too hot.



Thank you!

 

Start by checking Fuse 16 in the power distribution fuse box under the bonnet. It is a 5A fuse supplying one of the two voltage feeds to the fan control module.

If the fuse is OK, then we have to look further.
The ECM maybe referencing not only at the water temperature sensor but the oil temp sensor as well, which is located near the oil filter.
Could be worth checking if that sensor is working properly seeing you have changed the water temp sensor already (assuming that new sensor is compatible and working properly).
Both the engine coolant temp sensor and engine oil temp sensor have a voltage range of 0-5V and as the temperature increases, the sensors output voltages decrease. So on your cold engine checking the voltage on the Yellow wire to the oil temp sensor you would expect perhaps 4.5 to 5.0 volts, similarly to the engine coolant temp sensor.
As the engine warms up that voltage will reduce. If the sensor is already low voltage when engine cold, then it could be sensor or wiring issue.
If the sensor voltage is 4.5 to 5 volts when cold but doesn't noticeably decrease when engine gets up to operating temperature, then you either have a bad sensor or bad earthing wire within the loom from the sensor back to the common sensor ground wire from ECM plug pin 19 (Black/green stripe wire).

Hope this gives you some new things to check.
Good luck!

 

Faulty coolant temperature sensor?

 

Wow! This is amazing. You have no idea how frustrating this has been for me. I appreciate the quick and detailed response.

The car is actually my dad’s and I’m just helping him out. I only see the car during the weekends, which also adds to why this has taken so long. Will try to do what you said or maybe ask someone more qualified to do it, if needed.

I’ll keep you guys updated, for sure. Hope I can work on the car again soon.

@h2o2steam, THANK YOU VERY MUCH!!!

 

@Dell Gailey. Just replaced it as well. Fans still acting the same. Will try to test it, though, as suggested by @h2o2steam.

Thank you!