View source for How to Repair iPhone 12 Pro Max that does not detect battery and does not charge

{{Repair Guide|Device=iPhone 12 Pro Max|Needs equipment=Soldering Iron, Hot Air Station, Tweezer, Flux|Affects parts=Main Logic Board|Difficulty=4. Specialist|Type=Soldering}}

== Problem Description ==
An iPhone 12 Pro Max shows no charging and battery not detected, even after replacing the charging port, using a new cable and charging cable/brick.

* Battery connector voltage (BATT_VCC) reads 3.7–4.0 V (normal).
* Charging IC and USB IC measure fine.
* Battery FPC diode readings normal.

Root cause: low I²C voltage (0.2V instead of 1.8V) on SDA/SCL pins.

Tracing these lines leads to U2470, the battery data level translator IC.

Replacing U2470 restores I²C communication, allowing the phone to detect the battery and charge normally.
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[[File:12pm-u2470-batt-pins.png|thumb|iPhone 12 Pro Max - Battery Pins]]

== Symptoms ==

* iPhone does not charge or power from the battery.
* Battery percentage not displayed, device may only run on DCPS.
* No corrosion or damage visible on battery connector area.

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[[File:12pm-u2470-schematics.png|thumb|iPhone 12 Pro Max U2470 - Schematic]]

== Diagnostic Steps ==

# Measure Battery Connector Voltage
#* BATT_VCC → 3.7–4.0V = ✅ Good
#* If missing, diagnose power path first.
# Check Battery FPC Diode Mode
#* All lines read within normal range = ✅
# Measure I²C Lines (SCL/SDA)
#* Expected: ~1.8 V
#* Observed: ~0.2 V → indicates line is being pulled low.
# Trace I²C Lines to U2470
#* Locate U2470 (near battery FPC).
#* Check for damage/corrosion.
#* If clean, suspect internal short or failure pulling bus low.

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[[File:12pm-u2470.png|thumb|iPhone 12 Pro Max - U2470 Location]]

== Repair Steps ==

=== 1. Remove Faulty U2470 ===

* Use hot air station to remove U2470.
* Clean pads, inspect for shorts.

=== 2. Replace U2470 ===

* Install a new/reballed U2470.
* Align carefully.

=== 3. Verify Voltages ===

* After installation, re-check I²C voltage at battery FPC:
** Should now be ~1.8V.

=== 4. Final Test ===

* Connect battery, boot phone.
* Confirm battery is detected, percentage shows, and device charges.