Test F: DTCs B2844 and U2472 - Ignition Fault and Unexpected Ignition State

Pinpoint Test F: DTCs B2844 and U2472 Ignition Fault and Unexpected Ignition State
Refer to Vehicle/Diagrams, Power Distribution/SJB for schematic and connector information.

Normal Operation
When placed in ACC, RUN or START, the ignition switch sends voltage out to the smart junction box (SJB). Micro-processors in the SJB continuously monitor the ignition switch state. The ignition switch has 4 possible states:
^ OFF
^ ACC
^ RUN
^ START

When the ignition switch is placed in ACC, fused ignition voltage is sent to SJB C2280a-3 along circuit CDC33 (VT/GN).

When the ignition switch is placed in RUN, fused ignition voltage is sent to:
^ SJB C2280a-3 along circuit CDC33 (VT/GN).
^ SJB C2280e-1 along circuit CDC34 (WH/OG).
^ SJB C2208b-45 along circuit CDC34 (WH/OG).
^ fuse 35 (10A) in the battery junction box (BJB) along circuit CDC34 (WH/OG).

When the ignition switch is placed in START, fused ignition voltage is sent to:

Hybrid Vehicles
^ fuse 35 (10A) in the BJB along circuit CDC34 (WH/OG).
^ SJB connector C2280e-1 along circuit CDC34 (WH/OG).
^ SJB connector C2280b-45 along circuit CDC34 (WH/OG).
^ PCM connector C175b-21 along circuit CDC35 (BU/WH).
^ SJB C2280b-32 along circuit CDC35 (BU/WH).

Non-Hybrid Vehicles
^ fuse 35 (10A) in the BJB along circuit CDC34 (WH/OG).
^ SJB connector C2280e-1 along circuit CDC34 (WH/OG).
^ SJB connector C2280b-45 along circuit CDC34 (WH/OG).
^ PCM connector C175b-7 along circuit CDC35 (BU/WH).
^ BJB starter diode along circuit CDC35 (BU/WH), then through the diode to:
- SJB C2280b-32 along circuit CE619 (BU/BN).
- PCM C175b-4 along circuit CE619 (BU/BN).
- transmission range (TR) sensor C167-4 along circuit CE619 (BU/BN).

^ 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.
^ U2472 Unexpected Ignition State - If the SJB does not receive the ignition RUN signal, or any ignition switch signal, while carrying out an SJB self test, DTC U2472 is set.

This pinpoint test is intended to diagnose the following:
^ Wiring, terminals or connectors
^ Ignition switch
^ SJB

F1-F2:

F3-F5:

F5 (Continued)-F6:

F6 (Continued)-F8:

F8 (Continued)-F11: