Chart A1-2 Malfunction Indicator Lamp on Steady

Diagnostic Chart:

OBD System Circuit:

CIRCUIT DESCRIPTION
The Malfunction Indicator Lamp (MIL) will flash Diagnostic Trouble Codes (DTCs) when either the diagnostic request terminal in the Duty Check Data Link Connector (DLC) or the DIAG SW connector in the junction block are grounded.

CHART TEST DESCRIPTION
Numbers below refer to circled numbers on the diagnostic chart.

1. This will check for a grounded indicator circuit.
2. This will determine if it is an open diagnostic request terminal circuit, a poor ground connection or a faulty Engine Control Module (ECM).

DIAGNOSTIC AIDS
An intermittent malfunction may be caused by a poor connection, rubbed through wire insulation, or a wire broken inside the insulation. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals and poor terminal-to-wire connections before component replacement.