Diagnostic system — description [Toyota Carina T190]

The electronic control unit has a built-in system of current self-diagnostics, which continuously monitors the engine condition using sensor signals. If a malfunction is detected, this system identifies it and informs the driver about it with a warning signal "CHECK", which is illuminated by a control lamp located on the instrument panel.

Analyzing various signals (see below table of diagnostic codes), the electronic control unit determines the failed system based on the operating parameters recorded by the corresponding sensor or actuator.

A warning light on the instrument panel informs the driver of a malfunction. The light turns off automatically immediately after the malfunction is eliminated. However, the electronic unit stores in its memory the malfunction codes (usually, except for codes No.16, 43, 51, 53) associated with the corresponding failures until the diagnostic system is cleared (does not "reset" the information) by disconnecting the fuse with the ignition off.

If a malfunction is detected, its code will be displayed when operating in test mode (except for the codes indicated in the table). In this case, the terminals "TE2" and "E1" of the diagnostic connector must be closed.

When operating in test mode, even after the malfunction has been eliminated, the diagnostic code will be stored in the memory of the electronic control unit even when the ignition is off (except those mentioned above). This is also possible when working in the current self-diagnostic mode. Selecting the type of self-diagnostic mode (current or test) and the output of diagnostic codes is carried out by short-circuiting the terminals "TE1", "TE2" and "E1" of the diagnostic connector.