B2844

Steering Column Switches

Pinpoint Test F: DTCs B2844 and U2472

Refer to Wiring Diagram Set 13, Power Distribution/SJB for schematic and connector information [1][2]Diagrams By Number.

Normal Operation

Microprocessors in the Smart Junction Box (SJB) continuously monitor the ignition switch state.

If DTC U2472 was set immediately following an SJB (Smart Junction Box) on-demand self test. Clear the SJB (Smart Junction Box) DTCs and repeat the self-test making sure that the ignition is in RUN. If DTC U2472 returns again, continue with Pinpoint Test F.

- DTC B2844 (Ignition Fault)- If the SJB (Smart Junction Box) receives an invalid ignition state (one or more ignition signals at the same time) during normal operation, DTC B2844 will be set.

- DTC U2472 (Unexpected Ignition State)- If the SJB (Smart Junction Box) does not receive the ignition RUN signal or cannot detect the ignition switch state during the SJB (Smart Junction Box) self-test, DTC U2472 will be set.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors

- Ignition switch

- SJB (Smart Junction Box)

PINPOINT TEST F : DTCs B2844 AND U2472

NOTICE: Use the Flex Probe Kit for all test connections to prevent damage to the wiring terminals. Do not use standard multimeter probes.

F1 REVIEW THE SJB (Smart Junction Box) DTCs

- Review the DTCs retrieved during Inspection and Verification.

Is DTC B2A20 present?

Yes
GO to Pinpoint Test E Pinpoint Test E: DTC B2A20.

No
For DTCs B2844 and U2472, GO to F2.

For all other SJB (Smart Junction Box) DTCs, REFER to Body Control Systems.

F2 CHECK THE IGNITION SWITCH

- Ignition OFF.

- Carry out the Ignition Switch Component Test.

Is the ignition switch OK?

Yes
GO to F3.

No
INSTALL a new ignition switch. REFER to Ignition Switch . CLEAR the DTC. REPEAT the self-test.

F3 CHECK THE IGNITION SWITCH PIDs

- Connect: Ignition Switch C250.

- Connect the scan tool.

- Ignition ON.

- Enter the following diagnostic mode on the scan tool: DataLogger- SJB (Smart Junction Box).

- With the ignition in RUN, monitor the following PIDs:
- ECU Derived Ignition State-ACC (IGN_A_ECU)
- ECU Derived Ignition State-RUN (IGN_R_ECU)
- ECU Derived Ignition State-START (IGN_S_ECU)


Does the IGN_R_ECU PID display Yes and do the other PIDs display No?

Yes
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTC(s). REPEAT the self-test and TEST the system for normal operation.

No
If IGN_R_ECU displays No, GO to F4.

If IGN_A_ECU displays Yes, GO to F5.

If IGN_S_ECU displays Yes, GO to Pinpoint Test E Pinpoint Test E: DTC B2A20.

F4 CHECK THE IGNITION RUN CIRCUIT FOR AN OPEN

- Disconnect: Ignition Switch C250.

- Disconnect: SJB (Smart Junction Box) C2280B.

- Measure the resistance between ignition switch C250-1, circuit CE612 (GY/VT), harness side and SJB (Smart Junction Box) C2280B-45, circuit CE612 (GY/VT), harness side.





Is the resistance less than 5 ohms?

Yes
GO to F6.

No
REPAIR circuit CE612 (GY/VT). CLEAR the DTC. REPEAT the self-test.

F5 CHECK THE IGNITION ACCESSORY CIRCUITS FOR A SHORT TO VOLTAGE

- Disconnect: SJB (Smart Junction Box) Fuse 45 (5A).

- Using the scan tool, monitor the IGN_A_ECU PIDs:

Does the PID display No?

Yes
REFER to the Wiring Diagrams to identify the cause of the circuit short [1][2]Diagrams By Number.

No
REPAIR circuit CDC33 (VT/GN). CLEAR the DTC. TEST the system for normal operation.

F6 CHECK THE SJB (Smart Junction Box) CONNECTORS

- Ignition OFF.

- Disconnect: SJB (Smart Junction Box) C2280A.

- Disconnect: SJB (Smart Junction Box) C2280B (if not previously disconnected).

- Disconnect: SJB (Smart Junction Box) C2280E.

- Check the connectors for:
- corrosion.
- pushed-out pins.
- spread terminal.


- Connect: All Disconnected Connectors and/or Fuses.

- Make sure the connectors are seated correctly, then operate the system and verify the concern is still present.

Is the concern still present?

Yes
INSTALL a new SJB (Smart Junction Box). REPEAT the self-test, then TEST the system for normal operation.

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.