Hi, I've replaced my thermostat housing and coolant temp sensor, and now I've got a check engine light with a low coolant temperature voltage code. I am reading 3.5 volts at the sensor and I should be seeing 12. I do not have a schematic. Does anyone know the pin out coming from the computer to the sensor? Or at least which of the three cables holds the right wire? I don't want to open them all up to attempt finding the right wire. Thank you.

 

Do you have a cooper or Cooper S ? Whats the year ?

 

Sorry about that! 2006 clubman base.

 

2008 ?

 

Typo! 2011

 

Its ok, figured, because no clubman in 2006

The 6/2010 Cooper ( NON S ) to 3/2012 models when switching to the new 11537534521 will need that 12517646145 adapter lead harness.


https://www.ecstuning.com/Search/SiteSearch/11537534521/





&

https://www.ecstuning.com/Search/SiteSearch/12517646145/






Hence you are getting the codes.

 

Thank you. I did replace that adapter cable. That's the reason I thought it had to be voltage to the computer, or from the computer to the sensor. I don't want to cut open those cables to find the right wire if I can find the pin out on the right connector and avoid making a mess.

 

Ok, did you try looking at the harness cable also Y cable might be clipped in backwards. That is the green and the black tips plugs on the one end I believe are the same but have different function back to the main plug. Try that first.

 

Ok, just for grins I ordered and installed a new adapter cable from ECS. This did not help. The connectors are properly placed. At this point I'm back to tracing wires to determine why I haven't got the right voltage on the coolant temp sensor. Does anyone have a schematic for this car?? I cannot locate one anywhere!


Thank you.

 

Did you flip the two connections that are the same?

 

I did flip them, and get the same result. I'm thinking either the ecu is bad or I have a short. I nwed a schematic..

 

Dang, looks like a bad short or harness on the original side. Have you followed the wires and looked for chaffing , breaks ? Check the pinouts and make sure they are seated and not pushed back.

 

I have checked for shorts throughout the wiring harness (finally got a copy of the wiring diagram.) Now I'm wondering if its the ECU. If so, can I buy a used one and install it, or will I get problems because its from a different vehicle?

 

That's going to be tough on the Gen 2 , will have get new and to be flashed to the car. Before going to the ECU, I would check the pinouts and make sure the voltage is the same to the diagram you have. Most of the time its not an ecu problem, but a problem with the harness , did you swap connector end plugs and test?

 

Is there anywhere one can send the ECU for diagnostic testing? I'd like to know for sure if mine is good or bad before I do anything else or spend any more money on this.


Thanks!