Tesla Model 3/Y charge port ECU: Gen 4 and 1537264-20-B

Confirmed fact: Tesla treats the charge port ECU, the physical inlet and the high-voltage connection to the battery as separate components with separate service procedures. Manufacturer requirement: controller replacement is followed by a vehicle firmware reinstall, while some retrofits also require charge-port configuration. Editorial conclusion: matching appearance or model name alone is not enough to select a safe used unit.

What is the charge port ECU—and what is it not?

The charge port ECU is the control electronics around the inlet. It participates in communication between the cable and vehicle and supervises sensors and actuators associated with the port. It is not the externally visible CCS2 inlet, the high-voltage battery or the onboard charger that converts AC to DC.

That distinction matters during diagnosis. Tesla's owner's manual says a red charge-port light indicates a fault and stopped charging, but the cause may be the station, cable, an incompletely inserted connector, latch, wiring, controller or another vehicle system. One symptom does not prove ECU failure.

What do 1537264-20-B and Gen 4 mean?

Record the complete factory marking with hyphens: 1537264-20-B. Breaker databases often display it as 153726420B or P153726420B, but every digit and the final revision matter when searching and comparing. Gen 4 identifies the controller generation; it does not mean the unit is interchangeable across every CCS2-equipped Model 3/Y.

Tesla's current parts catalogue recommends a VIN search to select the correct catalogue and fitment. That is especially important on continuously produced models where inlet design, harness, battery connection or controller hardware may have changed during production.

Why Model 3, Model Y and model year are not enough

Tesla's 2017–2023 Model 3 manual contains both a standard charge port ECU replacement and a separate Combo Adapter retrofit, while the 2024+ Model 3 documentation explicitly identifies a Gen 4 controller. The 2020–2024 Model Y procedure says early cars accept only the white-enclosure ECU, while later bodies can accommodate both enclosure versions. These factory differences prove that several hardware and configuration paths exist—not that one part covers every car.

• verify the full VIN and production month;
• photograph the removed unit's complete label, including every hyphenated suffix and revision;
• compare connector count, shape and locking features;
• identify the European CCS2 inlet and harness or busbar design;
• check the supersession chain in Tesla's parts catalogue or through a qualified workshop;
• use a written diagnosis to confirm that the controller is actually faulty.

Software work is required after replacement

Tesla's Model 3 replacement procedure requires a vehicle firmware reinstall after the new ECU is fitted. The Combo Adapter retrofit also requires Native Charge Port configuration through Service Mode Plus or Toolbox. A unit that physically plugs in may therefore still fail to operate correctly without commissioning.

The exact action depends on vehicle configuration and repair goal. Before buying a used controller, the workshop should establish whether the job is a like-for-like replacement, a factory supersession or a retrofit, and whether the required Tesla diagnostic access is available.

Diagnose before buying a part

First record the complete touchscreen alert, charge-port light colour, AC or DC charging type, station, cable and whether the problem repeats on another known-good charger. Tesla states that solid amber can mean an incompletely inserted connector, blinking amber reduced AC current and red a fault.

If the problem persists at several known-good chargers, request Tesla-compatible diagnosis and targeted inspection of the inlet, latch, low-voltage supply, wiring, connectors and ECU. Only then should a replacement part be ordered.

Used-controller buying checklist

• a complete, legible 1537264-20-B label and undamaged housing;
• matching connectors, mounting points and market-region marking;
• source vehicle model, production date and market region;
• no evidence of impact, water ingress, corrosion or overheating;
• workshop-confirmed vehicle compatibility and software commissioning plan;
• warranty, return terms and post-installation AC/DC charging tests.

In short, 1537264-20-B is a useful exact search key, but it cannot replace VIN, hardware and diagnostic checks. A sound purchase compares the car's data and the removed unit's label in the same verification process.