Fan runs at full speed and Battery doesn't charge
I have a mid 2012 MacBook Air I'm working on with some strange behaviour I'm trying to diagnose. There is no SSD installed and I do not have access to one yet, so I'm using a USB drive for testing. The IO bridge cable is also missing, so USB and audio on the left side do not work.
To summarize: the fan ramps up to full speed as soon as power is applied (6500RPM), and the battery is completely dead and does not charge. The operating system boots fine and there is no slowdown typical of a bad temperature sensor throttling down the processor, though there is fairly high CPU usage (70 percent) on a clean install.
I am using a 60W MagSafe adapter with a new Magsafe 1 to 2 adapter. The charge LED does not turn on, no matter how the connector is oriented. The charger and indicator works fine with other 13 inch MacBook Pros and charges them as well. There is no damage to the adapter or the cable.
Apple Hardware Test fails with 4SNS/1/40000000: ICOR-16.495, meaning CPU 0 Current is out of spec.
- I have already performed multiple PRAM and SMC resets, but they have made no difference.
- I Installed iStat and the Chipset INA Highside shows a current of 16.50A.
- I swapped the battery with another one and it doesn't make any difference.
Here are the iStat readings:
BMU 1: 38
BMU 2: 36
CPU DIE: 51
CPU DIE CORE 0: 52
CPU DIE CORE 1: 53
CPU PROXIMITY 46
LOGIC BOARD: 34
PLATFORM CONTROLLER HUBS: 40/54
CPU System Agent: 0.78V
CPU Vcore: 0.77V
Int GPU Vcore 0.01V
PBus Rail 8.40V
CPU VCore 1.85A
Chipset INA Highside 16.50A
DC IN Rail AMON 0.66A
IG GFX Vcore 0.02A
The battery shows up as "not charging" at 0mAh charge remaning though it shows a cycle count of 506 and condition of Normal, so the battery is getting detected by the operating system.
I'm not sure if this issue is repairable as it seems to me that the issue is with the processor itself. Anything on the motherboard I can clean or check?
Any help would be greatly appreciated,