Normal Operation

The ignition switch receives fused battery voltage from Smart Junction Box (SJB) fuse 27 (20A) along circuit SBP27 (BU/RD). The ignition switch then sends that voltage out to various systems depending on ignition switch position. The ignition switch has 4 possible states:

• OFF
• ACC - Power on circuit CDC33 (VT/GN) to the SJB 
• RUN - Power on circuit CDC34 (WH/OG) to the SJB  and Battery Junction Box (BJB)
• START - Power on circuit CDC35 (BU/WH) to the PCM and the One-Touch Integrated Start (OTIS) diode in the BJB  . From the OTIS  diode, the voltage is sent to the SJB  , the PCM and the starter relay in the BJB  along circuit CE336 (GN/WH).

The SJB  continually monitors the ignition switch position and will set DTCs when certain conditions exist.

• DTC B2844 (Ignition Fault) - If the SJB  receives an invalid ignition switch state or cannot detect the ignition switch state during normal operation, DTC B2844 is set.
• DTC U2472 (Unexpected Ignition State) - If during the SJB  on-demand self test, the SJB  does not receive the ignition RUN signal or any ignition switch signal, DTC U2472 is set.

  This pinpoint test is intended to diagnose the following: 

• Wiring, terminals or connectors
• Ignition switch
• SJB