There are five different OBD-II communication protocols:
J1850 PWM
J1850 VPW
ISO9141
ISO14230 (also known as Keyword Protocol 2000)
CAN (ISO15765 / SAEJ2480)
What does this mean for me?
Well, generally, you’ll need to know which protocol you have when purchasing a code reader or OBD-II tool. Sometimes manufacturers label products for Ford, GM, etc., so it can be easy. However, here’s the quick way to tell what you have.
Note: At the time of writing, I don’t know if this is a 100% foolproof method to tell which protocol you have. Make sure to check with a dealership or repair manual if in doubt.
To find out which protocol you have, refer to the table below:
| Standard | Pin 2 | Pin 7 | Pin 10 | Pin 15 | Notes |
|---|---|---|---|---|---|
| PWM | must have | – | must have | – | The connector must have pins 2, 4, 5, 10, and 16 |
| VPW | must have | – | – | – | The connector must have pins 2, 4, 5, and 16, but not 10. |
| ISO | – | must have | – | must have | The connector must have pins 4, 5, 7, and 16. Pin 15 may or may not be present. |