Reading Diagnostic Trouble Codes

PRE-TEST CONDITIONS:

Prior to performing a self-diagnosis or testing of the system, make sure that all other related systems that can affect the operation of the ECI System have been checked and determined to be functioning properly.
Also, ensure that the battery is fully charged, as detection of input signals cannot be made when battery voltage is low. If the battery requires charging, perform a slow charge without disconnecting the battery cables. Disconnecting the battery cables for more than 10 seconds will erase all the current fault codes from the ECU memory.
Ensure all harness connectors are clean and securely connected. If wiring repairs are necessary, replacement wiring should be of the same type to prevent ignition and radio interference. Shielded wire is used between the ECU and ignition coil negative pole, as well as the body ground strap.



EXTRACTING CODES:

Turn ignition switch to the ``Off'' position. Connect a suitable voltmeter to the self diagnostic output harness connector.

Fig. 11 ECI diagnostic test connector.:

On Cordia and Tredia models, the connector, Fig. 11, is located in the engine compartment on the right hand side near the firewall.

Fig. 13 Self diagnosis signal indicating a system malfunction:

With ignition switch On, the indication of ECU memory contents will start. If the system is in normal condition, voltmeter reading should indicate a constant 12 volts. If any failure codes are stored in memory, the voltmeter reading will indicate pointer deflections, which reflect the voltage wave forms as shown, Fig. 13. After recording the malfunction code, check and repair each item as indicated by the diagnostic codes chart. After repairing defective components, clear diagnostic codes by disconnecting battery ground cable for approximately 15 seconds or until failure codes have been erased.