How to enable CCS1 adapter/NACS support on older Model 3/Ys
- Jul 8, 2022
- 7 min read
Updated: Jul 12
UPDATE - July 1, 2026: Important note. We no longer recommend buying the Gen4 ECU from any other sources except through Tesla because we have received many reports of unscrupulous sellers like on ebay who try to sell a package deal for a Gen4 ECU with a poor quality Bundle of Wires.
We found out the Gen4 ECUs can be used (even though it is advertised as new), broken or misrepresented as the correct part number, and the Bundle of Wires can be of poor quality and more unreliable due to being in an automotive environment with extreme temperatures and vibrations. Save yourself from the frustration, delays and extra expenses by buying from our recommended sources. There are too many things that can go wrong if the ECU doesn't work properly. The best chance your DIY retrofit will be successful is to buy the right Gen4 ECU from Tesla.
Here is a recent case of someone buying a package deal from ebay. The ECU he received was advertised as a new 1537264-00-B Gen4 ECU, but in fact, it was a used, broken 1537264-80-B Gen4 PCB assembly (no CCS capabilities) disguised in a 1537264-00-B shell. Also, the included Bundle of Wires was of poor quality and there was no way to tell if it would even work because the ECU was broken.
As of March 10, 2024, Tesla's official retrofit is now available. You can either schedule the retrofit via a service request or do this DIY retrofit. The Tesla's retrofit is $350 and includes the CCS1 adapter.
The following DIY retrofit solution for older Model 3s is a proven solution with over 2000 successes over a 4 year period. It will only take 10 minutes to complete once you get all the parts.
In order to use non-Tesla DC fast chargers from networks such as Electrify America or ChargePoint, your older Model 3/Y will still need to have CCS enabled (i.e. CCS1 retrofit) regardless if the plug is NACS/J3400 or CCS1. Only difference is the CCS1 Adapter is not needed if it is a NACS plug. This is because the communication behind the NACS/J3400 plug is still CCS (PLC) and not Tesla (SWCAN). This is mentioned in section 4.5 of the Tesla NACS Technical Specifications document.
There are 2 types of DIY retrofits for the Model 3/Y either A or B. Estimated install time: 10 minutes - Level of difficulty: Easy
Retrofit A. If your EV is a North American (NA) Model 3 and made AFTER October 4, 2020 (built with black trim, heat pump and refreshed dash) or a NA Model Y without CCS enabled, all you need to do is swap out the charge port controller (ECU) to the full-featured Gen4 ECU which is Tesla part number 1537264-00-B or 1537264-01-B. Users also have reported 1537264-10-E (smaller black one) will work, but may not mount to the car in the same way.
Purchase 1537264-00-B or 1537264-01-B or 1537264-10-E (black) from a Tesla Service Center or from EPC (epc.tesla.com) for $140 + sales tax. This is not a restricted part so there is no reason why you shouldn't be able to purchase it. You may need to be assertive.
Remove your existing ECU and install the new one (see this video on how to swap out). Per the service manual, there is no need to disconnect any power (12V or main traction).
Retrofit B. If your EV is a NA Model 3 and made BEFORE October 5, 2020 (built with chrome trim), all you need to do is swap out the charge port controller (ECU) to the Gen4 ECU which is Tesla part number 1537264-00-B or 1537264-01-B, and add a third party wire harness called "A Bundle of Wires with a Board" in line with the Gen4 ECU. Users also have reported 1537264-10-E (smaller black one) will work with our bundle of wires, but may not mount to the car in the same way.
Purchase 1537264-00-B or 1537264-01-B or 1537264-10-E (black) from a Tesla Service Center or from EPC (epc.tesla.com) for $140 + sales tax. This is not a restricted part so there is no reason why you shouldn't be able to purchase it. You may need to be assertive.
Purchase "A Bundle of Wires with a Board" from 2 Much Sun for less than $62 either here or on ebay or you can build your own with instructions in this post. There are other third party makers of "a bundle of wires" especially from China. We've heard that those are of poorer quality and may not work. 2 Much Sun sells the original bundle of wires with the same premium quality and 100% tested with a one year warranty on workmanship. 2 Much Sun's proven solution works 100% for thousands of users.
Remove your older Gen3 ECU and install the new one along with "A Bundle of Wires with a Board"(see this video on how to swap out). Per the service manual, there is no need to disconnect any power (12V or HV).
NOTES:
The service manual recommends reinstalling the software as soon as possible to prevent excess drain on the battery.
Once your EV supports the CCS1 adapter, you may want to buy the CCS1 adapter from the Tesla store in order to use non-Tesla DC fast chargers with CCS plugs. You might need to wait a day before ordering so that the store is updated with the change in CCS adapter support status to allow you to buy it.
For support and questions, check out the Community Forum.
Q: Is this retrofit still needed for non-Tesla DC fast chargers with the NACS/J3400 plug?
A: Yes. Behind the NACS/J3400 plug is still CCS so your Model 3/Y will still need to be CCS enabled in order to communicate to any non-Tesla DC fast charger.
Q: Are these safe retrofits?
A: Yes. Both retrofits use Tesla's Gen4 ECU and there has been over 2000 "A Bundle of Wires" sold in the last 48+ months without any confirmed problems or charging limitations due to the retrofit. Since there are no high voltage or high current circuits in the ECU, it is not necessary to touch any of the high voltage or high current components (including the thick orange wires) in either retrofits, making it completely safe for a DIY project. In fact, the Tesla service manual doesn't require the vehicle to be powered down or 12V disconnected when swapping out the ECU.
Here are some detailed reasons why this is a safe retrofit:
The Gen4 ECU supports the CCS protocol plus some Gen4 charge port hardware specific features (port heater, an internal cover, different thermistor type, and built in proximity resistor). The Gen4 charge port hardware is installed in all the Model Ys and Model 3s built after Oct 4, 2020 while the older Model 3s (built before Oct 5, 2020) use the Gen3 charge port hardware.
The Gen4 ECU and Gen4 charge port hardware were originally released together to support CCS but due to some supply chain issues, Tesla made a version of the Gen4 ECU (1537264-80-B) without CCS support and started using those whenever they needed to deliver cars but didn't have enough of the fully populated Gen4 ECUs. This is why the Retrofit A is very safe and is just as Tesla designed and released.
However, Retrofit B is a little more challenging because it reuses the Gen3 charge port hardware by using "A Bundle of Wires with a Board" to feed the proper signals into the Gen4 ECU by remapping matching wires and adding 4 resistors. The resistors help tune the low voltage logic level signals to be similar or equivalent to the expected signals in order for the Gen4 ECU to work properly with the Gen3 charge port hardware.
Q: Does this void my warranty?
A: The technical answer is no. However, if you have a failure in the charge port, Tesla could claim it is not covered because of the added board and wires with the Gen4 charge port ECU, but Tesla will need to provide backup.
In the US, the Magnuson-Moss Warranty Act prohibits product manufacturers like Tesla from conditioning consumer warranties on the use of any original equipment part or service. Furthermore, a manufacturer can only deny warranty coverage if it can demonstrate that a non-original equipment part or related service caused a defect to occur in the original product. In other words, they can't just say it but rather have the burden of proof. Other countries have similar consumer protection laws such as the Canadian Consumer Protection Acts.
The schematics to this retrofit is publicly readily available. Anyone who is in the trade can do the analysis and will conclude this retrofit is safe and 100% compatible with the existing design. The analysis shows that this retrofit is extremely unlikely to cause any damage if correctly or incorrectly installed or even if there was a quality defect. There are also over 36+ months of additional real world use data out there with over 2000 retrofits with no issues caused by this retrofit.
In addition, troubleshooting is easy because this modification is fully and easily reversible without leaving any physical signs that it was ever done. So if you have a charge port failure, reverse the retrofit (reinstall your original ECU, remove "A Bundle of Wires ...", if applicable, and reinstall the software) and if it still doesn't work then it's not the retrofit causing the failure.
Q: Will this retrofit allow me to still use Superchargers and CHAdeMO adapters?
A: Yes, this retrofit will not reduce or remove any existing charging options (both AC and DC charging) already available on your vehicle. For example, if your vehicle can use Superchargers, it will still be able to use Superchargers after this retrofit. If your vehicle has Supercharging disabled, it will still be disabled after the retrofit.
Q: It says it is a DIY solution. What does this mean?
A: You will need to install this yourself as this not a Tesla offered solution. It is as easy as changing out a battery or tire, but a lot less work.
For Retrofit B, for example, you will need a 10 mm socket wrench and a screw driver or trim fastener removal tool. Remove 2 fasteners on the trunk trim, pry open the carpeting behind the charge port while disconnecting the trunk light, unscrew 1 bolt holding old ECU, install new ECU along with "A Bundle of Wires with a Board", reassemble in reverse, and reload software. It should take about 10 minutes of your time not including time for a software reload. See latest video here.
If you want to know even more details on Retrofit B, you just need to read the first post in this long TMC topic.
