Truthfully, unless you’re replacing your car’s port or something, the OBD2 protocol that’s used by your vehicle doesn’t matter.
Modern OBD-II scan tools can interface with vehicles with any implementation of the standard.
As long as you’ve got an OBD2 scan tool and a car produced after 1996, you should be able to connect the two regardless of make, model, or specific protocol.
This article will show you all the details about the OBD2 protocol that is supported by your vehicle.
Table of Contents
- 1 OBD-II Protocols: Which OBD-II Protocol is Supported By My Vehicle?
- 2 Can I Tell What Protocol My Car Uses By Examining the Connector?
- 3 Where is the Connector Located?
- 4 What Is OBD-II?
- 5 Does My Vehicle Contain OBD-II?
- 6 Finding the Right OBD-2 Scan Tool For Your Vehicle
OBD-II Protocols: Which OBD-II Protocol is Supported By My Vehicle?
Modern scan tools can communicate with all types of OBD-II systems. It almost certainly does not matter what particular subsystem your car uses. Nevertheless, here’s a quick rundown of some common OBD-II protocols.
Connector Types: Type A vs Type B
While most scan tools can plug into both Type A and Type B connectors, there’s a slight physical difference between the two types of ports.
Type A connectors have 16 “teeth” in two rows of 8 sandwiching a single “tongue,” while Type B connectors have the same 16 “teeth” sandwiching a “tongue” that’s split in two.
Again, your scan tool probably can plug into both types of connectors without any problems.
Five Protocol Types
There are 5 common implementations of the OBD-II protocol that are in use today.
Think of these like the accent that your car has when it talks to your scan tool. Your scan tool can still understand cars with different accents, but the way the various cars “talk” might sound a little bit different.
Here are the types:
1. ISO 15765-4 CAN (SAE J2480)
This protocol is used in a variety of vehicles that aren’t subject to the OBD2 standard by law.
Pins 6 and 14 should be there, while the metallic contacts should have pins 4, 5, 6, 14 and 16.
A variant of this is used in most newer cars since newer car computers need the unique features this protocol offers to communicate effectively.
2. ISO14230-4 (KWP2000)
Pin 2 is a must. The connector must have material contacts inside pins 2, 4, 5, and 16. However, pin 10 should not be there. You sometimes find this protocol in some Asian cars.
3. ISO 9141-2
This protocol is frequently found in Chrysler vehicles, as well as European and Asian cars.
4. SAE J1850 PWM
If the connector has pin 2 and pin 10, the protocol is J1850 PWM. The connector should also have metallic contacts inside pins 2, 4, 5, 10, and 16. This protocol is usually used by Ford Motor Company.
5. SAE J1850 VPW
Pin 2 is a must. The connector must have material contacts inside pins 2, 4, 5, and 16. However, pin 10 should not be there. This protocol is mostly used by General Motors.
Can I Tell What Protocol My Car Uses By Examining the Connector?
Yes. Each protocol uses a different pin to communicate with a scan tool.
By carefully examining the inside of the “teeth” on the serial bus, you can figure out which pins are in use and which sockets are left empty. This enables you to figure out the protocol that your car uses.
Again, though, your scan tool simply has a receptacle for every protocol. It does not matter what your car uses unless you’re doing something complicated (like replacing your connector).
If we number the top 8 pins 1-8 from left to right and number the bottom 8 pins as 9-16 from left to right, here’s what each pin is used for:
Pin 1: Reserved for OEM COMM
Pin 2: This is where your J1850 Bus+ is located
Pin 3: OEM Reserved
Pin 4: This is just a car chassis ground
Pin 5: Similarly, this pin holds a sensor signal ground
Pin 6: OEM COMM. Here’s your CAN high pin (J-2284). Most modern cars (2008+) will have this pin and a set of other pins, including pins 4, 5, 6, 15, and 16.
Pin 7: This is your ISO 9141-2 K line
Pin 8: OEM Reserved
Pin 9: OEM COMM
Pin 10: Here’s your J1850 Bus- (negative) (note the location relative to pin 2)
Pin 11, 12, 13, 14 OEM Reserved
Pin 15: ISO 9141-2 L-line. This is right below the matching K line.
Pin 16: Unswitched Battery Power. This powers your scan tool.
All cars produced after 2008 have more advanced computers that require the CAN protocol and will have similar pin configurations (4, 5, 6, 15, 16). Cars produced before then have a bit more variance with which pins are used.
You can identify which protocol your vehicle is supported by having a look at the pin-out of the OBD2 connector.
|Standard||Pin 2||Pin 6||Pin 7||Pin 10||Pin 14||Pin 15|
|ISO 15765-4 CAN||Must have||Must have|
|ISO14230-4 (KWP2000)||Must have||Optional|
|ISO 9141-2||Must have||Optional|
|SAE J1850 PWM||Must have||Must have|
|SAE J1850 VPW||Must have|
Where is the Connector Located?
OBD-II connectors have to be located on the driver’s side of the car or within a couple feet of the centerline of the car. They have to be accessible from either the driver’s seat or the front passenger’s seat.
They’re usually located under the steering column. Less frequently, they’re sometimes found under the glove compartment.
If you can’t easily find the connector, you can use your favorite search engine to find out exactly where it’s located in your particular vehicle. Be sure to include the make, model, and year in your search.
While there are a couple subtypes of OBD2 systems, there’s no practical difference between where the connector is located.
The standard has shifted slightly over time, but most connectors are still found below the steering column.
OBD2 stands for “on-board diagnostics”. The “2” differentiates it from a similar protocol that existed in the state of California prior to 1996. Since 1996, OBD-2 systems have been required by law to exist on every car in the United States.
The point of OBD2 is to provide car owners and mechanics with a standardized way of interfacing with car computers and retrieving diagnostic data. Prior to the OBDII standard, car manufacturers each used their own special scan tools and error codes.
If your car had a problem with its engine, your mechanic had to use a device specific to your particular make of car.
Even if he or she had such a tool, they’d need lots of experience with your make of car in order to make sense of the unique error code it gave them.
OBD-2 solves that problem by requiring every car to follow a universal standard.
This means every scan tool can hook up to every type of car. Once you’re connected, most error codes are standardized across every OBD-2 equipped car.
Some manufacturers like to send additional data that might not work with every scan tool, but this information comes on top of the normal suite of standard diagnostic features and error codes.
It’s also still pretty universal: many modern scan tools can read manufacturer specific information from just about every make and model of car.
Does My Vehicle Contain OBD-II?
If your vehicle was made after 1996 for use in the US, yes. This includes vehicles made by foreign companies.
In other words, unless your car is very old or there’s something weird going on, your car has an OBD-II system.
Finding the Right OBD-2 Scan Tool For Your Vehicle
Most modern OBD2 scan tools support all protocols and connector types.
No matter what type of car you have, if it was made after 1996, it’ll work fine with pretty much every scan tool.
If you’ve got a newer (2008+) car, however, you may want to find a scan tool that specifically offers functionality that takes advantage of the more advanced CAN protocol. This can let you change the settings on your car’s computer and view more advanced diagnostics and real-time data.
Read NOW my latest Review of the Best OBD2 Scanners and take one for your vehicle.