B2739

DTC B2739 Key In Ignition Fault:

DTC B2739 Key In Ignition Fault (Part 1 Of 2):

DTC B2739 Key In Ignition Fault:

CIRCUIT DESCRIPTION
The Body Control Module (BCM) interfaces with the ignition key alarm switch. The ignition key alarm switch grounds circuit 80 when the key is fully inserted in the ignition switch. The switch opens when key is removed from the ignition switch. The BCM uses this input for the operation of the key in ignition reminder, exit illumination, and lockout prevention. The ignition key alarm switch receives ground through circuit 1550.

CONDITIONS FOR SETTING THE DTC
^ The BCM does not detect a ground in circuit 80 when the BCM is detecting voltage in circuit 1500
^ All conditions must be present for more than 0.3 seconds.

ACTION TAKEN WHEN THE DTC SETS
The BCM stores DTC B2739 in memory.

CONDITIONS FOR CLEARING THE DTC
^ The BCM receives a key in ground signal (circuit 80) when the ignition switch is not in the LOCK or OFF position, then the BCM changes the DTC status from current to history.
^ A history DTC will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present.
^ Using a scan tool.

DIAGNOSTIC AIDS
^ The following conditions may cause an intermittent malfunction to occur:
- An intermittent open or short to ground in circuit 80.
- An intermittent open in circuit 1550.
- Poor connections at the BCM or the ignition key alarm switch.
- The BCM is shorted to voltage internally.
- An intermittent open in G203.
^ The BCM is open internally.
^ DTC P1626 will set in the Powertrain Control Module (PCM) when the ignition switch is in the RUN position with the BCM disconnected. When BCM diagnostics and repairs are completed, refer to the Engine Controls for additional information on PCM related DTCs. Powertrain Management

TEST DESCRIPTION
Numbers below refer to the step numbers on the diagnostic table.
3. Determines whether circuit 80 or 1550 is open, or the ignition key alarm switch is faulty (contacts always open).
4. Checks for either short to ground in circuit 80 or a faulty ignition key alarm switch (contacts always closed).
5. Determines whether the malfunction is intermittent or the BCM is faulty.
6. Checks for an open in circuit 1550.
7. Checks for either an open circuit 80 or a faulty ignition key alarm switch.
8. Checks for either a short to ground in circuit 80 or a faulty ignition key alarm switch.