Endgate Will Not Open in the Accessory Key Position - keywords ECM glass ignition key park PCM rear TCM transmission V8

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

Endgate will not open with the key in the accessories position. With the key in the Accessory position, the ECM will indicate the transmission gear position as 'In Gear' regardless of the actual shifter position. If the key is placed in the 'Run' or 'Start' position the ECM will display Park/Neutral when the transmission is in park or neutral and 'In Gear' when the transmission is placed in any position other than Park or Neutral. 'In Gear' is the ECM default when the key is NOT in the Start/Run position.

Note: The TCM will display the correct transmission position in all key positions.

In order for the endgate to open, the ECM must provide the endgate module with the transmission shifter position - the endgate will only open with the transmission in Park - and with the key in Accessories position the ECM is communicating 'In Gear' even though the transmission is actually in park.

This is normal operating characteristics for the V8 LH6 and no repairs should be made. When comparing vehicles, it is important to compare operation to a like vehicle with the same engine size.

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.