There may be a Tailgate Ajar message displayed on the Driver Information Center even though the tailgate is fully closed on some 2022–2026 Silverado 1500, Sierra 1500; 2024–2026 Silverado 2500/3500 and Sierra 2500/3500 models. (Fig. 8) In some cases, the minor/inner and/or major/outer tailgate also may not release when commanded.
Fig. 8
Tailgate Ajar Message
The Tailgate Ajar message is not based solely on the input to the Body Control Module (BCM) on ajar signal circuit 7295. The message also can be displayed if the BCM commands the minor/inner tailgate to release. In this situation, the BCM assumes the tailgate has opened because it issued a release command to the tailgate relays, even if the gate did not physically open and no corresponding ajar signal was received. Since the BCM commanded a gate release, it turns on the tailgate ajar message.
If the BCM commands a tailgate release but does not receive the tailgate ajar signal on circuit 7295 because the gate did not open, it will disable additional release commands. This typically occurs after approximately three release attempts without a valid ajar signal input. Once the BCM disables the release function, the taillamps may flash at a faster rate when a tailgate release button is pressed, indicating that additional release commands have been inhibited.
This tailgate operation can make diagnosis more challenging because the BCM may appear to be inoperative when it has intentionally disabled the release function due to the missing tailgate ajar input. To help restore release command operation for diagnostic testing, disconnect the vehicle’s 12V battery for one minute and then reconnect it. After power is restored, the BCM will allow a limited number of release attempts and the taillamps should flash at the normal rate.
Tailgate Diagnosis
Begin diagnosis of the tailgate by checking for DTCs related to the Tailgate Ajar signal circuit 7295. Address any faults by following the appropriate Service Information. Possible faults may indicate issues with the tailgate release system, such as tailgate release relays KR192, KR191G and KR191S (Fig. 9); fuse F17DL; release actuators; related circuits; grounds; and other components that control the tailgate release actuators.
Fig. 9
In addition, after performing the battery disconnect and reconnect procedure, listen closely for the tailgate relay or relays to click when a tailgate release button is pressed. Keep in mind that the BCM will allow only a limited number of release attempts before disabling the function again if a valid ajar signal is not received.
Verify relay operation to help identify the next diagnostic step. If both the major and minor tailgate functions are inoperative, but the relays can be heard cycling, inspect circuit 7730 for an open or high-resistance condition and check for an open fuse. The major and minor tailgate actuators share circuit 7730 as a ground path and use the same fuse for power, making these common areas to inspect when both gates are inoperative.
Refer to #PIT6543 for additional information.
– Thanks to Jim Will
