MacBook Air M2
USB-C Charging Fault
CD3215 vs T6002 Diagnosis

Understanding the USB-C Power Path

MacBook Air M2 units (A2681) feature two separate USB-C controllers: CD3215 (left port) and T6002 (right port). Both handle full power delivery and charging negotiation independently. When only one port delivers power, isolate the fault to the corresponding controller before condemning the entire charging subsystem.

The charging path flows through USB_PD_SRC_P and USB_PD_SRC_N rails, feeding ISL6259 buck regulators that output 20V nominal to the battery management IC. A typical healthy current draw under full charge is 45W at the USB-C connector, which translates to approximately 2.25A at 20V.

The MacBook Air M2 A2681 repair guide covers comprehensive logic board diagnostics; this article focuses specifically on bifurcating CD3215 and T6002 faults.

Diagnostic Workflow

Step 1: Initial Voltage Rail Check

Connect a USB-C power adapter delivering 20V minimum output. Measure the following rails on the live board without disconnecting the battery:

Step 2: Resistive Isolation

Disconnect the battery. Use a multimeter set to 2 kΩ range. Probe continuity and resistance from each controller IC pin to ground and to adjacent decoupling capacitors. Typical expectations:

• CD3215 / T6002 power pins (VDDA, VDDB) should measure 100–500 Ω to ground through 1 µF/10 µF capacitors.
• No shorts (< 10 Ω) between power and ground except through intended inductors.
• Signal pins (CC1, CC2, DP, DN) should float above 500 kΩ until actively signaled by the host adapter.

A hard short on any power pin indicates physical damage, moisture corrosion, or solder bridge—replace the controller IC.

Step 3: CC Line Negotiation

Reconnect the battery. Measure the pull-down voltage on the CC1 and CC2 pins of the affected port using a DC voltmeter:

• Healthy state (no cable): 0.8–1.2V (internal pull-down within controller).
• Healthy state (cable inserted, before negotiation): 0.4–0.6V (5.1 kΩ pull-down on adapter side pulls controller reference lower).
• Healthy state (after negotiation): 0.55–0.90V (settled to negotiated voltage per USB PD 3.0 spec).
• Fault state: Voltage stuck at 0.0V (short), 3.3V (pull-up missing), or does not respond to cable insertion.

Component-Level Replacement

CD3215 (Left USB-C Port)

The CD3215 is a 32-pin QFN (5×5 mm). Identify it near the left USB-C connector. BGA/micro-ball rework is required; use lead-free solder paste (SAC305 alloy). After heating to reflow temperature (240–250 °C peak), apply flux bridging across the pads, then remove solder bridges with desoldering wick or hot air to achieve 0.3 mm spacing.

Test point FP0_DP should measure ~3.3V internally when the port is idle. FP0_CC1 and FP0_CC2 pull toward ground through the internal network. Any voltage present when the port is inactive suggests a stuck pull-down or shorted capacitor.

T6002 (Right USB-C Port)

The T6002 is a similar 32-pin QFN package installed near the right USB-C connector. Replacement procedure mirrors CD3215. Confirm the chip orientation by checking silkscreen markings and component datasheet alignment—reversed orientation causes all signals to float or lock high.

Supporting Passives

Each port has associated decoupling capacitors (typically 1 µF / 10 µF ceramic X7R rated for 10V minimum) and pull-down resistors (5.1 kΩ 1% metal film). Swollen or leaky capacitors near either controller are a common secondary fault. Replace them in pairs if one fails; do not mix old and new.

Post-Repair Integration Test

Power-On Self-Test

Connect the battery and power on the MacBook Air M2 without the external adapter. The SMC should initialize normally and the display should come on. If the board powers up during this step, the logic board is not hard-shorting.

Now insert a known-good USB-C power adapter (minimum 20V 3A output) into the repaired port. The System Report should show "Battery Power" transitioning to "AC Power" within 1–2 seconds. If the transition is slow (5+ seconds) or fails, the negotiation is incomplete—check CC line timing with an oscilloscope.

Thermal Load Test

Run Cinebench R24 or geekbench for 10 minutes while connected via the repaired port. The power adapter input should read steady 20V at approximately 2.0–2.5A under CPU load. Battery charge percentage should increase at a rate of 2–3% per minute when idle and charging simultaneously.

If current spiking occurs (sudden drops to 0.1A or spikes above 3A), the power management IC is oscillating—likely secondary damage to the ISL6259 voltage regulator.

Cross-Port Verification

Repeat the full test sequence on the second USB-C port to confirm both controllers function independently. A truly healthy M2 board can charge from either port at full 96W output when using a suitable multiport adapter.

Common Failure Modes & Prevention

Overvoltage spike: Defective third-party USB-C power supplies delivering > 24V to the port directly damage the VBUS input of the CD3215 and T6002 ICs. The ESD diode clamps usually fail first; secondary cascade damage affects the voltage regulator. Advise users to use only Apple or certified USB-C PD adapters rated explicitly for 20V 5A or higher.

Repeated insert/removal stress: The USB-C connector solder joints—not the controllers themselves—fail under mechanical fatigue. However, when the connector cracks internally, it creates intermittent shorts across VBUS and GND. Monitor resistance stability across the positive rail during thermal cycling.

Moisture ingress: MacBook Air M2 casings are relatively sealed, but liquid damage near the USB-C zone can bridge the fine-pitch traces on the controller. Apply conformal coating (acrylic, not silicone) on the USB-C breakout area if the unit has humidity history. Include a small cutout over the test points for future diagnostics.