J1772 was the Society of Automotive Engineers (SAE) cable-based EV or PHEV vehicle-to-charger connection specification.

While many vehicle manufacturers initially adopted J1772 as their primary vehicle-to-charger spec for their EV product lines, other manufacturers did not.

J1772 is currently in the process of being replaced in North America by the NACS/J3400 specification. Please see What is NACS? or What is J3400? for more information.

The North American Charging System was first conceived and developed by Tesla.

This system was a series of specifications that described how vehicle-to-charger connections should be made, and what the physical connection mechanism would look like.

This standard enabled Tesla to develop their vehicle product lines independently of their charging station infrastructure projects and networks.

It ensured that when a Tesla vehicle rolled off the line, it could connect to any of their charging stations, and work seamlessly.

Because Tesla has built the largest EV charging network in the world, there was strong incentive for other vehicle manufacturers to take advantage of this charging network for their own vehicles, to allow their customers to have more choice in charging locations.

NACS has proven so popular, that the Society of Automotive Engineers (SAE) used this as the basis upon which to develop the J3400 specification.

At this time, all vehicle manufacturers that sell vehicles in North America have adopted the new NACS/J3400 specification for their own usage and advantage. All new vehicles and vehicle platforms sold from Model Year 2027 and beyond will come with a NACS/J3400 port on them.

The success of NACS forced the abandonment of the J1772 vehicle-to-charger specification that SAE previously created for this similar purpose.

The Society of Automotive Engineers (SAE) created J3400, which describes vehicle-to-charger connection specifications.

J3400 has become known as the North American Charging Standard. While its foundation is almost entirely modelled off of Tesla’s proprietary NACS specifications, J3400 involved multi-industry and multi-stakeholder input to design and create, providing a comprehensive final specification.

The result? J3400 is the new North American Charging Standard. This standard will be followed by all vehicle manufacturers that sell EVs and PHEVs in North America.

It was designed to replace J1772, and also be fully compatible with Tesla’s proprietary charging network, allowing any vehicle implementing J3400 to charge their vehicle on Tesla’s EV charging network, which is currently the largest single entity charging network in the world.

J1979/J1979-2 are the SAE specifications that support On Board Diagnostics – Generation 2 (OBD2/OBDII).

OBD2 is a standardized framework deployed across all Light-Duty passenger vehicles sold in North America since 1996. OBD2 allows generic access to vehicle data and controls through a standardized connector (traditionally called the OBD2 port). Required by law, this framework facilitates delivery of important vehicle data and access to functional tests or reports for critical vehicle systems, especially those systems and components related to emissions control.

There are typically two main reasons why a vehicle is not listed as compatible:

1.  Vehicle Diagnostic Link Connector Incompatibility

A Vehicle’s Diagnostic Link Connector (DLC) traditionally serves as a primary location for external tools or devices to connect to vehicles and gain access to vehicle data.

For many EVs built in the last decade, especially those built by Non-Legacy Vehicle OEMs, there may non-traditional methods of getting data off of a vehicle, and in some cases there may not be a DLC on the vehicle at all!

This is rapidly changing through the adoption of a new standard called J1979-3!

• Starting at a penetration rate of 40% of all EVs Model Year 2026, eventually reaching 100% of all vehicles by Model Year 2027, the new J1979-3 standard being enforced requires EV vehicle manufacturers to have a standardized Diagnostic Link Connector present inside the vehicle.

The reason diagnostic connector discrepancies exist in the EV market, is because EVs in the modern era did not initially have to conform to the same diagnostic standards as traditional ICE vehicles.

• For traditional ICE vehicles, emissions regulations and the OBD2 standard called for a common Vehicle Diagnostic Link Connector to be used on all vehicles sold in North America.
• • This connector was required to be present in all Internal Combustion powered Light Duty passenger vehicles sold in North America since 1996.
• For EV vehicles, where there is no Internal Combustion Engine or tailpipe emissions, EVs did not have to adhere to the OBD2 standard.
• • Many EVs built and sold by Non-Legacy OEMs in their early years of establishment, built vehicles without a standard diagnostic connector at all. They were simply not required to support the physical presence of this connector.
  • Non-Legacy OEMs preferred non-traditional methods of connecting to vehicles, which meant gaining access to even the most basic vehicle data was entirely proprietary. 

2.  Vehicle Data Unavailability

Even if your vehicle does have a Diagnostic Link Connector (DLC) that CleverKey can plug into, it may be unable to retrieve or decode the data from your vehicle.

There are known EV vehicle examples where vehicle diagnostic data is not available from this connector at all, or the way data is read from the connector is entirely proprietary, and CleverKey may not be able to retrieve it.

This is especially true for Non-Legacy Vehicle OEMs, where there is no real guarantee of data availability primarily due to lack of standardization across the EV industry.

This is rapidly changing through the adoption of a new standard called J1979-3!

• Starting at a penetration rate of 40% for all EVs Model Year 2026, eventually reaching 100% of EVs by Model Year 2027, the new J1979-3 standard being enforced requires EV vehicle manufacturers to provide a standardized set of Data Parameters through a standardized Vehicle Diagnostic Connector.

For traditional ICE vehicles, emissions regulations and the OBD2 standard made generic vehicle diagnostic data and parameters available through a standard diagnostic connector.

• This was required on all Light Duty Passenger Vehicles sold in North America since 1996.

For EV vehicles, where there is no Internal Combustion Engine or vehicle tailpipe emissions, these same rules did not apply.

• EVs were not required to support the OBD2 standard, therefore many Non-Legacy Vehicle OEMs had no reason to support a standardized way of providing even the most basic diagnostic vehicle data.
• Many EVs built and sold by Non-Legacy Vehicle OEMs in their early years of establishment instead had entirely proprietary ways of getting data off of vehicles.
• This was a stark contrast to Legacy Vehicle OEMs who have begun building EVs. These OEMs have retained standard/traditional ways of connecting with a vehicle to provide diagnostic data.