Why is my CPU running over 100% and AHT gives 4SNS/1/40000000 TsOP--124?

Hi Guys,

My MBP ran without any issue until 2014 mid and then it started to make fan noise(running at 6200rpm), and fans were always running. Then it started to give charging issues. When I plugged my charger in it quickly blinks amber and then goes out and will not charge the battery. But some times it charged the battery. Now Machine is very slow and kernel task is always over 100%.

When I ran AHT it gave 4SNS/1/40000000 TsOP--124 error. And TG pro shows all the sensors in working condition, but PalmRest sensor is not showing in the list even.

I am helpless at this stage and here I don't have apple stores to repair this. Apple reseller in here telling me to replace the logic board without inspecting this issue deeply. I want to find whether a failed thermal sensor cause this problem and if it is, which one is the failed one(Palmrest/Optical drives/Power bus).

Thanks

Update

Hi Dan,

I de-assemble my MBP to check that upper case keyboard ribbon cable and found this. One of the Capacitor or Resister(I can not identify the item) is burnt, is it relevant to this issue. Please give a look and advice me.

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Good catch! I would start there.

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That looks like C7555 10UF 16V 10% capacitor in a 0805 package. Verify your logic board number. It is a 820-XXXX number imprinted on the logic board itself.

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Thanks - OT!

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No problem at all.Anytime...

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Hi OT,

My logic board number is 820-2936-B. And found this code (HF/e1) near that code too. So can you please verify the exact capacitor for me. Otherwise I have to buy a broken logic board to get this item and it will cost me much.

Thanks Dan and OT!

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Here's a good article on how to interpret AHT: How to invoke and interpret the Apple hardware tests.

You are correct your error 4SNS/1/40000000 TsOP--124 does imply the palm rest thermal sensor.

Did you spill anything into the keyboard or track pad? If you did it sounds like you have some corrosion on the keyboard flex circuit where the sensor is located.

Here's the IFIXIT guide to get to the ribbon cable: MacBook Pro 13" Unibody Late 2011 Upper Case Replacement. As you can see its quite a bit of work to even get to it.

You may want to conceder getting a replacement upper case.

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Thanks Dan for your fast reply. I was also referred that cnet article to interpret the AHT error code. I am wondering now Palmrest proximity sensor is responsible for all three Palmrest,Optical drives,Power bus units which indicate by sOP. Or that error code implies the error could be in Palmrest or in Optical drives or in Power bus. I got your message"You are correct your error 4SNS/1/40000000 TsOP--124 does imply the palm rest thermal sensor" and I am asking this again just to clarify.

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The upper case keyboard ribbon cable is where the sensor is located. It is a single sensor. Are you confused on how to decode the AHT code? The OP--124 is the conditional code. It really doesn't matter here as you either need to clean or replace the upper case.

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That cap is not causing the sensor issue, the liquid damage to the trackpad is. Replace, and clean the board in 99% alcohol and a baking tray from the corner store for $1. Find a dead board for $30 or so online to steal parts from that is the same 820-2936 that yours is. That cap, while not being good that it is blown, is not going to be the start all end all of whether your laptop works or not. Liquid damage elsewhere is causing the charging issue.

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Now I am confused. I thought Charitha Basnayake stated that "replaced the burnt C7555 10UF 16V 10% capacitor in a 0805 package with a new one. Now mac is running without any issues. Battery is charging now. Palm-rest sensor is detecting now. And processor running with out fan noise. Test run is passed" Are you saying that it is not?

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OT - You're both right here! The start of this was likely something spilled into the keyboard onto the ribbon cable. Depending on what it was it may still have issues. It appears the amount of liquid was enough to blow the cap which is what you identified OT. This is a tough one, as its a lot of work to investigate to make sure if the ribbon cable is not corroded.

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Blah, I forgot to hit add more. That is weird. I just removed that cap from an 820-2936 Here and it even passes ASD.

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Charitha Basnayake will be eternally grateful.
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