Retrieving Codes (Non-Scan)
- Turn ignition on. Do not start engine. SERVICE ENGINE SOON light should glow. Locate Assembly Line Data Link (ALDL) connector attached to control module wiring harness. Most ALDL connectors are located under dash on driver's side of vehicle. For location of ALDL, see COMPONENT LOCATIONS illustration in SYSTEM/COMPONENT TESTS
article in this section. Turn ignition on with engine not running. Insert jumper wire from terminal "B" (diagnostic test terminal) to terminal "A" (ground) of ALDL connector. See Fig 1
.
NOTE:
Inserting jumper wire into test and ground terminals of ALDL connector with engine running will cause fuel injected vehicles to enter field service mode. Flashes of the SERVICE ENGINE SOON light will not indicate codes if this is done. See FIELD SERVICE MODE in BASIC TESTING
article in this section.
Courtesy of GENERAL MOTORS CORP.
- SERVICE ENGINE SOON light should begin to flash codes. Each code will be repeated 3 times. If codes are not flashed or SERVICE ENGINE SOON light does not illuminate, perform DIAGNOSTIC CIRCUIT CHECK in BASIC TESTING
article in this section. To exit diagnostic mode, turn ignition off and remove jumper wire from ALDL connector.