For 1990-2009 cars

Step | Action | Normal Result(s) | Abnormal Result(s)*
--- | --- | --- | ---
1 |

1. Connect the scan tool to the data link connector (DLC).
2. Turn the ignition switch to the RUN position.
3. Attempt to establish communication with the UART serial data line.

• | The scan tool operates.

• | The scan tool communicates with the UART serial data line.

• | Scan Tool Inoperative

• | Scan Tool Does Not Communicate with UART Data Line

• | Scan Tool Does Not Communicate with UART Data Line

2 | Attempt to establish communication with the Class 2 serial data line. | The scan tool communicates with the Class 2 serial data line. | Scan Tool Does Not Communicate with Class 2 Data Line
3 | Attempt to establish communication with the E and C serial data line. | The scan tool communicates with the E and C serial data line. |

• | Scan Tool Does Not Communicate with E and C Data Line

• | Scan Tool Does Not Communicate with E and C Data Line

* Refer to the appropriate symptom diagnostic table for the applicable abnormal result.