Entering Or Exiting Diagnostic Mode
NOTE:
The Assembly Line Data Link (ALDL) connector is also referred to as the Data Link Connector (DLC). This is the same connector.
- With ignition on and engine off, connect a jumper wire between Data Link Connector (DLC) terminal "B" (diagnostic terminal) and terminal "A" (ground). See Fig 1. The Diesel Electronic Control (DEC) system will enter diagnostic mode.
- In this mode, ECM will display DTC 12 by flashing the MIL once, followed by a short pause, then 2 flashes in quick succession.
- DTC 12 will be displayed 3 times. If no other codes are stored, DTC 12 will continue to flash until diagnostic terminal is ungrounded. To exit diagnostic mode, turn ignition off and remove jumper from DLC connector.