Normal Operation
WARNING: This page is about a different car, the 2014 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.
Battery voltage is sent to the ignition switch from the Battery Junction Box (BJB) fuse 28 (15A). When placed in ACC, RUN or START, the ignition switch sends fused battery voltage along 1 of 3 circuits to the Body Control Module (BCM). Microprocessors in the BCM continuously monitor the ignition switch state.
- DTC B1142:29 (Ignition Status 1: Signal Invalid) - this DTC sets when the BCM does not receive a valid ignition state signal during the BCM self-test.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Ignition switch
- BCM