No Crank No Start SES Lamp On - keywords dtc P0741 P2761 P0716 P0717 P0843

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

There have been multiple cases of either single or multiple transmission DTCs reported on 2006-2007 Buick Lucerne. The condition has found to have been caused by a partially seated transmission connector. The 2006-2007 Buick Lucerne has a dual lock connector on the transmission side, but a single lock tab on the harness side. The weight of the harness has been found to cause a partial connection resulting in an SES light or transmission shift concern.

With a TECH 2 connected and set to capture any DTC, start the engine and wiggle the connector at the transmission. If any DTC is captured, disconnect and reconnect the transmission connector and secure the harness to prevent future disconnects.

The harness side connector will be redesigned to add dual lock tabs as a rolling change in the 2007 model year.

Other reference on a similar subject 2006 Lucerne DTB 06-06-04-021

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.