Retrieving Codes

NOTE: Trouble codes may also be referred to as DTC(s) or codes.

Code retrieval starts with DIAGNOSTIC CIRCUIT CHECK. The MIL light comes on when ignition is on and engine is not running. When engine starts, MIL light should go off. If light remains on while engine is running, a trouble code is present.
If light did not come on with key on and engine off, see CHART NO. 5. If MIL light fails to operate, see DIAGNOSTIC CIRCUIT CHECK. Circuit checks are located within code charts.
To retrieve codes, install jumper wire between White and Black wires of ALDL connector, located behind left kick panel near ECM. See Fig 1 .

Fig 1: Locating ECM & ALDL Connector
Courtesy of ISUZU MOTOR CO.
Turn ignition on and count number of flashes from MIL. A Code 12 will be a flash, pause and flash, flash. A long pause will occur. Code 12 will repeat 3 times. See Fig 2 . Each additional code will flash 3 times, starting with lowest number code to the highest number code. Once all codes are displayed, codes will be repeated.
If system is operating properly (with no codes), a Code 12 should exist with ignition on and engine off. This indicates diagnostic system is working. Remove jumper wire from ALDL connector after codes are retrieved.

Fig 2: Code Display (Typical)

Courtesy of ISUZU MOTOR CO.