[Rocco]

Hi,

The problem started with error code P0118, that indicates possible issue with engine coolant temperature (ECT) sensor.
The ECT sensor itself is OK. There is no 5V between sensor signal - sensor ground line.

I need to further check the wiring line from ECT to ECM (ECU), but I need the pinout of the ECM(ECU) plug connector, to locate the other end of ECT sensor signal and ECT sensor ground, to see if the problem is in wiring or maybe in the ECU.

P.S. The temperature gauge indicator is also not functioning at all

Thanks!

[Dazzler]

Welcome Rocco, I can't help, but you post has good info to help others with a diagnosis.  Well done.

[tw2005]

Something worth mentioning. the pinouts for the manual and auto are different according to the manual. This image is identical to the auto version but note it says GND is pin 35 for the manual but has pin 73 highlighted wjich is what they say the Auto is.

[tw2005]

[Rocco]

Thanks for your replies!

I checked the wiring between ECT sensor and ECU/ECM connector, and the wiring is OK.
The problems that now remain is:
- There in no 5V between ECT Signal and ECT Ground, which indicates certain ECU/ECM problem
- Temperature Gauge indicator in the instrument cluster is not working (OBDII reading is -40 deg C)

Is there something more that I can check or do by myself? Like reboot the ECM, or reset it?
What could be the relation of temp. gauge indicator with ECM (if indeed there is ECM problem). Or perhaps the temp. gauge problem might be related with some fuse or something similar? Can I check something more here, as well?

[Dazzler]

Hi again Rocco,

If you disconnect the negative terminal for a minimum of 30 minutes it will apparently reset the ECU/BCM and has been known to fix the odd fault. (Worth a try)

[nzenigma]

I don't think you have an ECM problem, but need to give some more thought to this... tw's posts are good too .cheers for now

[Rocco]

Hi,
Just to make some update.

I disconnected the negative terminal for a 30+ minutes, for resetting the ECU/BCM. That didn't make difference, still the check engine light is on, and P0118 error code. I tried some other things, but no luck.
Since it's been 2 months with this problem, and it is risky to drive the car with no coolant temp indication, (although is winter here, and radiator cooling fan is always on, I guess as precaution due to the no temp info available).

So if there are no more suggestions what I can do by myself, I'll probably decide to go to official Hyundai service, to make diagnostic there, and pay expensive check up.
They might even suggest to replace the ECU/BCM module, and I will have to do that.

Regards, and thanks for all the info and suggestions so far.

[Dazzler]

Thanks for the update. Hopefully it doesn't come to that (replacement ECU)