DTC B2739: Key-In-Ignition Fault: Description

When ignition key is inserted fully in ignition switch, BCM receives a ground input through circuit No. 80 (Light Green wire) from ignition key alarm switch. BCM uses this input for operation of key-in-ignition reminder, exit illumination and lockout prevention.

DTC B2739 will set when BCM detects that Ignition 0 battery feed circuit No. 1500 (Purple wire) is and a ground signal is not received through circuit No. 80 for more than 0.3 second. No driver warning message will be displayed.

If BCM receives a key-in-ignition signal (ground) when ignition switch is not in LOCK or OFF position, a current DTC will change to a history DTC. If conditions for malfunction no longer exist, history DTC will clear after 100 consecutive ignition cycles. DTC B2739 will also clear when scan tool is used to clear codes.

NOTE: When ignition switch is turned to RUN position with BCM disconnected, PCM-related DTC P1626 will be set. After BCM repair is completed, see appropriate TESTS W/CODES article in ENGINE PERFORMANCE section:

TESTS W/CODES - Century
TESTS W/CODES - Regal