iMac Intel 27" EMC 2309 (Late 2009, Core 2 Duo 3.06 or 3.33 GHz) ID iMac10,1, EMC 2374 (Late 2009, Core i5 2.66 GHz or Core i7 2.8 GHz) ID iMac11,1

384 Questions View all

Will HD replacement fix the problem?

My late 2009 iMac, 11,1, 4core i5, 2.66 GHz, Mavericks, will only boot up in safe mode. It will not boot from a FW800 HD, or a USB HD, nor a OS 10.6.2 optical disk. It shows all of this with option restart, but just like the internal HD boot, all stop at the Apple logo gray screen.

This was a sudden event, away from home and returned to find frozen with black screen, would only start in safe mode. Repaired permissions and verified & repaired drive. Can boot a MBPro from this drive in target mode.

I used optical drive to run a hardware test. With short test: error code 4MOT/4/40000003:HDD-1248 or -1243.

With long test: error code 4MOT/4/40000003:HDD-1273 consistently.

SMARTReporter does not show problems (safe mode)

From what I read the error indicates HD needs replacing, but will replacement solve the problems?

Answered! View the answer I have this problem too

Is this a good question?

Score 0


I'm having the same problem.

Did you solved the problem?


did you install a temp & fan monitoring program to see whats happening? Did you clean out the dust buildup internally? More often than not the issue is heat is not dissipating correctly due to dust or blocked vents.


Add a comment

2 Answers

Chosen Solution

It might. See this iMac Hardware Error 4MOT/4/40000003: HDD-1316 to a similar problem - the numerals are about how far it is out of spec. I think it's worth trying the "extra fast fan speed" briefly - before swapping the HD... or while you in there to do the HD blow out any dust you can.

If this Answer is helpful please remember to return and mark it Accepted.

Was this answer helpful?

Score 2


I have not solved my problem. I use the iMac in safe mode for what works and use other my computer options for video and sound. I tried the Smcfan control,it shows temps and fan speeds but appears unable to run in safe mode (it does not show up in "Library/Preferences" after install and fans do not respond to slider controls). Running hardware test does increase fan speed dramatically but I have run this many times, a small amount of dust came out the first time none since. When I have time to take this beast apart I will try to come back and post outcomes.


Mavericks is at 10.9.2 now… Have you thought about doing a data backup, wipe the drive and go back to the OS that originally came with your machine (at least to see if it is a OS not a Hardware problem? Could you create a original OS USB or external drive boot disk? Mavericks IMnsHO was released very green…. (a normal procedure for M$ - something new to the Mac OS).


Add a comment

Update to my iMac problem - When I updated to Mavericks 10.9.2 Smcfan Control began to work and after a number of days running fans at moderate to high speeds the harware test returned no errors, everything checked out. Nonetheless it was still only possible to boot in safe mode.

In response to the suggestion about completely erasing the drive and re-installing software, that was one of the first things I tried with no benefit. And the iMac would not boot from any external boot disk, optical drive nor firewire.

The resolution to my problem made no sense to me:

When I finally made time to take it in to Apple none of their diagnostic software run at the Genius Bar detected any problems. They proposed to replace the hard drive to see if this resolved the problem (labor was only $39, so not bad, total about $200). When I was called to pick up the iMac I was told that the problem was the video card ($192). The worker who brought out my iMac could not explain why a video card would cause my problems (he thought nothing was visible to display). If Time Machine successfully completes a back up then all problems are gone...

Was this answer helpful?

Score 1


Did your temp monitoring software show your GPU running hot? There have been a rash of systems loosing there cooling liquid in the heat transfer tubing on the GPU heat sink.


Dan, It did not run hot. At least not while it was only bootable in safe mode. Never saw anything over 39 C. It may have run hot leading up to safe mode only operation, but I have no data for that period.


Apple did do a firmware update for this system, its possible that was the issue and the genius just didn't know what the tech did in the back room (could have even been sent to the regional repair depot). I guess the real question here is are you still having issues?


Add a comment

Add your answer

Sam C will be eternally grateful.
View Statistics:

Past 24 Hours: 1

Past 7 Days: 10

Past 30 Days: 27

All Time: 1,259