MacBook won't boot after trying to repair with Disk Utility. Cannot boot in Safe Mode. Just powers down after about 5 minutes. Apple Hardware Test says error 4SNS/1/40000001:IG0C-0.265 But I cannot find anything on the net about it. MacBook 4,1 Intel.

Question

Hello Everyone,
I am in dire need of assistance I am hoping someone could provide. I have a MacBook 4,1 with Intel Core 2 Duo processor 4GB Ram. It is taking over 10 minutes to boot up past the gray apple screen when I turn it on. First I cleared the PRam (?) then I checked the disk using Disk Utility Verify, and it said the disk needed repairs. So I ran the disk repair and it said it was unable to fix the errors on the HD.
I did a little research and tried booting into the Single User mode, then running /sbin/fsck -fy. It said that it found errors but could not fix them. I ran it two more times as suggested and got the same result each time. I then tried rebooting and now instead of taking 10 minutes to boot up, it takes about 5 minutes on the gray apple screen and then just turns off. I started in Verbose mode to try to troubleshoot the error and it appears the last thing to come across the screen before power down is a message "Apple Yukon 2: RxRingSize <= 1024....etc".
I decided next I would run the Apple Hardware Tester. The test came back with an error code "4SNS/1/40000001:IG0C-0.265". I am very good at searching the web but I could not find any errors that had the IG0C or IGOC or any combination at the end, but plenty of 4SNS/1/40000000(1) errors with different endings. From what I can tell people are saying anything with 4SNS/1/4000000 is a logic board failure, but this computer was literally just booting this morning until I did the /sbin/fsck -fy.
Any suggestions are welcome and appreciated.
Thank you for your time.

Answer 1

You've a couple of issues .... when Disk Utility tells you it can't repair a drive, if the error is a soft error, like an invalid tree or node, Disk Warrior (or TechTool Pro) can handle it. However, if Disk Warrior (or TechTool Pro) can't handle it, you can erase and write zero's to the hard drive and restore to it, or you can buy a new hard drive. Sometimes running SMART Utility can provide additional insight into the health of the hard drive. 
THe 4SNS error is a sensor error.  You could install iStat Pro to see if something is indeed getting too hot or remaining room temp or less.  You may need to take it into an Apple shop so they can use their thermal diagnostics to test and isolate it further.