RETRIEVING CODES (WITHOUT SCAN TOOL)
Note. The Assembly Line Data Link (ALDL) may also be referred to as the Data Link Connector (DLC).
Scheme 72
- With key on and engine off, locate Assembly Line Data Link (ALDL) connector under dash, on driver's side of vehicle. Connect a jumper wire between ALDL terminal "B" (test terminal) and terminal "A" (ground terminal). (Scheme 72) This places control module in diagnostic mode. NOTE: Connecting terminals "A" and "B" of ALDL connector with engine running will cause fuel injected vehicles to enter field service mode. The MIL (SERVICE ENGINE SOON) light will not flash codes if this is done.
- In this mode, control module will display DTC 12 by flashing MIL (SERVICE ENGINE SOON) light. DTC 12 is identified by MIL (SERVICE ENGINE SOON) light flashing once, followed by a short pause, then 2 flashes in quick succession.
- Each DTC will be repeated 3 times. DTC 21 is identified by 2 flashes, a short pause followed by one flash; DTC 53 is identified by 5 flashes, a short pause followed by 3 flashes. DTC's are separated by slightly longer pauses.
- DTC's are displayed in numerical order. Each code is displayed 3 times. DTC's will continue to repeat as long as ALDL test terminal is grounded. If DTC's are not flashed, or MIL (SERVICE ENGINE SOON) light does not glow, self-diagnostics will not work. See CHART A-1 under DIAGNOSTIC CHARTS.
- If MIL (SERVICE LIGHT SOON) light glows steadily, see CHARTA-2 under DIAGNOSTIC CHARTS. To exit diagnostic mode, turn ignition off, and remove jumper wire from ALDL connector.
Note. DTC's will be recorded at various operating times. Some codes require operation of sensor or switch for 5 seconds; others may require operation for 5 minutes or longer at normal operating temperature, road speed and load. Therefore, some codes may not set in a service bay operational mode, but may require road testing vehicle in order to duplicate condition under which code will set.