TIA to everyone with knowledge…I get this “error “ every time I start my 2006 C4 MT. I’ve tried adjusting the seat to no avail. Two Indy shops find no codes present but the temp solution is to have a passenger in the seat.

 

Check under the passenger seat and make sure nothing slipped under there I got that error and found an old water bottle.

 

If this does not help, you can disassemble the yellow connector under the seat, check the contacts and clean them.
Edit: Sensor is 7L5980948C and 997.618.233.03 is the control...

 

If taking apart the yellow connector, disconnect the battery first (DONT LATCH THE FRUNK). The airbag controls are in that yellow connector. This looks like a passenger weight sensor for the airbag message to me. Will likely require a scan tool to clear.the error once the problem is fixed as airbag errors don't clear on their own even when the problem is resolved.

 

Following, similar issue.

 

Two sensors are used for airbags; one in the seat bottom and the other in the backrest. Seat bottom does the weight assessment (and presence) and seat back checks the status of the person (leaning forward or back in seat) and also checks for presence.

Most vehicles will warn you of this when the seat cushion sensor is triggered but not the back sensor. I get this when I place a heavy case of mineral water bottles on the front passenger seat of my other cars. The fact that it disappears when someone is in the seat could verify this. You could try having the passenger sit in the seat but not lean back or touch the backrest to see if the error appears again. If so, the lower sensor must be stuck closed. No error code would be thrown in these circumstances.

Just a thought...