I have a late 2012 MacBook Pro with Retina Display and recently I've had some issues with it. Firstly it began to not charge properly - the charger light would stay orange and never go to green, and it wouldn't boot up (I imagine the battery was discharged and was failing to charge). This seemed to resolve itself but lately it has been unusable due to the system being extremely sluggish (taking 10 minutes just to open Safari), and the fans being at top speed constantly.

After some research I discovered I could run the Apple Hardware Test to diagnose any hardware failures/issues, and it indeed find a failure with the code below

4SNS/1/C0000008: Ts0P--124

After some research I discovered this is an issue with the palm rest temperature sensor - which makes sense as obviously the system is running away with itself and running the fans at max speed. I've tried resetting the PRAM and SMC to no avail.

I'm unable to get an appointment at the Genius Bar for at least a week and I do not drive so I can't drive to one with more availability so I'm wondering if there is anyway to fix this myself. If not, would this likely require a full logic board replacement or is the sensor quite simple to replace?

1 Answer 1


The temperature sensor is built into the track pad assembly so if you choose to undertake this repair, this is the part your are going to have to replace.

MacBook Pro trackpad, PN#922-9063

The PN# for the track pad for MBP 2009-2012 is PN# 922-9063. The good news is that it's under $30 at the time of this writing.

To change out your track pad, you will need to remove the battery from the top case assembly. iFixit.com has an excellent tear down which details how to do this.

Note: You won't have to completely disassemble the unit, but you will have to remove the battery to gain access. You can remove it by gently prying it up with a plastic putty knife. I have even seen dental floss used to slowly work the battery loose.

MacBook Pro battery location

If you are not comfortable doing this repair, I suggest you let a tech handle the repair.

I was able to find a YouTube video showing the battery removal. Once it's removed, you will be able to get a good idea of where the track pad is located.

MacBook Pro, top case assembly with logic board removed

  • Thank you for such a detailed and helpful answer - I've found this part and will have a go at a repair I think!
    – Chris
    Aug 5, 2016 at 7:13

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