MacBook Pro M4 Pro - no keyboard / trackpad / lid sensor

[mitchw]

Hello
I got this MacBook Pro M4 Pro to have a look at.
It was tiny bit liquid damaged, just the edge of the board got 1 small 10x10 mm area wet. I've seen much worse that still worked fine to be honest.
Since it was liquid damaged, warranty does not apply anymore.

Anyways it was checked at an local Apple Store and they discovered that it needs new trackpad, new top case, etc. Also it needed a new lid angle sensor which they replaced.
The main issue was that the screen remained black.

Anyways I cleaned the liquid damaged area, put the machine back together and I noticed this:
- Internal keyboard not working. However I can turn on the machine with pressing any of the keys.
- Trackpad also dead
- Machine will not sleep / turn off LCD, when lid is closed

So now I am thinking the whole issue might be just with the Lid Angle Sensor which they replaced at an Apple Store but they might forgot to calibrate.
Or there might also be an issue with the trackpad which I discovered was sitting bit uneven, and when I took it off, 3 out of 4 metal shims were missing! One of them was lodged beneath one of the trackpad springs. I am guessing the technician removed this trackpad to check for the liquid damage, and since there was none, he just put it back, but lost the shims.
Or perhaps this is indeed a Logic Board issue. Sadly I can't find the schematics for it. I compared it to the M3 MBP14 board, but they are quite different.

[mon2]

Review this:

https://www.youtube.com/watch?v=u18D...hannel=AhaTron

[mitchw]

Thanks. I checked it out. On their machine the sensor is working, but not at the right angle.
Mine is completely dead, it does not register opening/closing it no matter the angle.

Which is weird as it was just replaced. I could try moving the magnet by 180 degrees, but I am thinking that the lid sensor is not even initialized (programmed). I read somewhere that new Lid Angle Sensor needs to be initialized, otherwise it will not work at all.

What about the non-working trackpad / keyboard?
I guess I should replace the trackpad first?

[mitchw]

Also forgot to add, but running the diagnostics throw following errors:
NDR008 NDK001

[mon2]

https://discussions.apple.com/thread...06?sortBy=rank

check your keyboard cable.

[mitchw]

https://discussions.apple.com/thread...06?sortBy=rank

check your keyboard cable.

Ok!
I checked. Keyboard and trackpad cables are both fine.

[mitchw]

I replaced the trackpad with a new original Apple part and it is still not working :/
I still have to replace the angle lid sensor but I am not sure if will cause the trackpad/keyboard not to be functional

I am bit lost on this one.

[mitchw]

I decided to check SPI and I found the computer does not detect any SPI devices (it should detect trackpad and keyboard).
Next I again remeasured the Lid Angle Sensor voltages and found 2 voltages missing:
- SPI_AOP_LAS_MOSI_1V8 (0V)
- SPI_AOP_LAS_MISO_1V8_R (0V)

Other voltages are present, as well as SPI_AOP_LAS_CLK_1V8 which is at 1.8V
As the schematics are not available I can't trace them.

[mitchw]

I made some progress, I updated to the latest MacOS 26 Tahoe and it immediately prompted me to calibrate the Lid Angle Sensor. I did the configuration and now the Lid Angle Sensor is working. So apparently it was fine, just not calibrated.

But trackpad/keyboard are still not functional. Diagnostics say that the trackpad is not compatible with this model, despite being the right one. So I am guessing there might be more SPI problems. I perhaps could try doing the DFU restore, but the last time I tried, it failed due to trackpad being not connected (it was, but not detected)...

[mon2]

Hunt for and validate any level shifters that should be present between this trackpad and the main bus master (PCH).

[mitchw]

Will do. From what I've seen the level shifters for the keyboard/trackpad SPI are mostly the same on M3 MacBook Pro 14.

Anyways I managed to "brick" the system, I tried doing the DFU and it failed mid process. Now I only get the dreaded exclamation mark.
I tried to do the DFU multiple times and from 2 different machines, both fail with same error: (7) 130C.FFFF
My guess is that this means that it failed because of the missing trackpad. Interestingly it also failed before, but almost at the beginning, so it didn't do anything. Last messages in the updater log suggest that it failed to update firmware of one device, most likely trackpad.
Most likely it wasn't detecting the lid sensor and therefore it failed.
So note to myself (and others): next time, don't do a DFU if the machine is booting into the OS!

[mitchw]

Fixed!
UT340 level shifter was bad and also the DZT400 zener diode. The output (IPD_MCU_INT_CONN_L) connects to the 1st pin of the JT400 (trackpad connector), and when I was initially checking the 1st pin, and it being grounded, I assumed it is what it is, because lots of times the 1st pin on the connector itself is ground. In fact, it connects to the UT340 and DZT400. The zener was shorted to ground, and the UT340 was reading O/L on the diode check. Most likely a careless technician caused this problem.

After replacing both components, putting everything back together, I was able to do the DFU restore with no trouble, and machine came back to life, fully functional.

So to debrief:
-Non working keyboard / trackpad was caused by bad UT340 and DZT400
-Non working lid sensor was caused by uncalibrated lid sensor that the official repair shop forgot to calibrate
-The original trackpad is working just fine, so it was reinstalled back into the chassis