SERVICE (Wrench) Telltale

The SERVICE (Wrench) telltale is pulled to ground by the PCM. When the lamp is pulled to ground, current from the ignition circuit flows through the telltale lamp, allowing it to come On. The PCM will turn the SERVICE (Wrench) telltale On for all non-emission related diagnostic trouble codes (DTCs) that require that a telltale be turned On (some DTCs do not turn on a telltale but are stored to aid in diagnosis).

The SERVICE (Wrench) telltale will also be turned On if the ABS control module has detected a fault in its own warning indicator system. If the ABS system cannot turn on its own telltale, a message will be sent to the PCM through the class 2 data bus (circuit 1807) to turn on the SERVICE (Wrench) telltale.

The SERVICE (Wrench) telltale will be turned ON for 2-3 seconds when the ignition is turned to RUN for a bulb test.