The OBD Diagnostic Circuit

This unidirectional data stream typically consists of 14 to 20 data words representing primarily sensor inputs and three outputs; injection pulse width, spark advance angle, and idle speed control command. Data is transmitted at a rate of 100 baud, updating on the Diagnostic Tester display approximately once every 1.25 seconds. Depending on application, the data is accessed from either DLC 1 or DLC 2. Data is triggered by grounding the TE2 circuit and reading the VF1 circuit.

Diagnostic Trouble Codes can be displayed using the Diagnostic Tester or by grounding the TE1 circuit and counting the Malfunction Indicator Lamp (MIL) flashes. The scan tool reads codes by counting the low voltage pulses on the W terminal of the Diagnostic Link Connector (DLC). Therefore, code retrieval is a relatively slow process, especially when multiple codes are stored.

Diagnostic Trouble Codes can be displayed using the Diagnostic Tester or by grounding the TE1 circuit and counting the Malfunction Indicator Lamp (MIL) flashes. The scan tool reads codes by counting the low voltage pulses on the W terminal of the Diagnostic Link Connector (DLC). Therefore, code retrieval is a relatively slow process, especially when multiple codes are stored.

2002 Toyota 4runner Dlc Terminal
Do It Yourself Car Diagnosis

Do It Yourself Car Diagnosis

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