Passenger Presence Module code B0081 0f / passenger seatbelt light

hallal999 · February 23, 2022

I've been fighting the good fight trying to eliminate a SRS warning light on the dash of my 2008 Chevy Suburban LTZ. I ended up replacing both front impact sensors as one was obviously bad (swollen, cracked) and the other didn't look great. This did not correct my SRS light on it's own. After clearing the codes the light intermittently returns and goes away. Scanning with a code reader gives me B0081 0f Passenger Presence Module Erratic. I did find a service bulletin stating several variations of the B0081 code. Most point to a specific problem whereas the 0f version says basically communication lost with module. The TSB says don't change the module but address the other issues and the codes (including the 0f version) should clear.

In addition I randomly get the passenger seatbelt light illuminated on the overhead console when no one is in the seat.

I intend to pull the passenger seat and inspect the connections with the hope that I just have a loose connector but anyone else that has had a similar issue that wants to chime in on a specific spot to check would be appreciated.

Is there a chance the passenger seat buckle mechanism has gone bad and could be triggering the SRS light and B0081 0f code? This is just a guess since the passenger seatbelt light comes and goes as well.

dna9656 · February 24, 2022

Could be the seat belt; you can replace the belt of course but I would look into a test first. MAYBE short out the sensor and see if the light goes out. Not very scientific or sophisticated but it should work; therefore I wouldn't do it until I read what GM has to say. If I recall from my GM dealer school days (back in the late 90s) connections in the safety related systems are critical. You have to back probe connectors, I remember they had a test crimp thing, you crimped it onto the wire you wanted to test, (it stayed on the wire forever) and it had a probe hole in it you could insert your VOM teats lead tip into it to check for what ever you were checking for then when you removed the test lead a fluid inside the crimp flowed over the probe hole to protect the wire from corrosion. I am pretty sure this was on air bag circuits but hey, why not on seat belt wires?

AS I have stated many time in this forum any time you get weird electrical problems you can not discount bad grounds. You always have to consider them and I consider them first as they don't cost any money (if you do the work) to track down and since bad grounds can be the simplest of solutions logic dictates that you search them out first. How's it go... "Occam's razor, also called the 'law of parsimony', is a philosophical idea, mental model, and problem solving principle developed by English theologian William of Ockham in the 14th century.. The principle states that if there are multiple hypothetical explanations to a problem, the explanation that makes the fewest assumptions is most likely to be the right one."

hallal999 · February 24, 2022

Good suggestion with the ground. I'll poke around to see if there is a ground in the area while I have the seat out. I intend to get into it tomorrow (weather permitted). If I find a solution I'll post the results.

hallal999 · March 7, 2022

Just a short update on the ongoing passenger SRS warning light battle. I pulled the passenger seat this weekend and found two things of note related to the clues I had.

1st anything related to SRS components have a safety clip involved. Knowing this helps identify potential targets to explore. Yellow seems to be the color for airbag components. I found a connector near the seatbelt buckle with a blue safety clip. I disconnected, cleaned, used a bit of dielectric grease and reconnected it. This seems to have solved the occasional passenger seatbelt warning light I was getting on the overhead console. The location of this connector could easily be affected by someone shoving something between the seat and the center console. However, this did not correct the original SRS dashboard light. Code "B0081 0f" still is present.

2nd I found a wire harness wrapped with blue metallic tape (?) that was slightly unwound exposing a multitude of jacketed wires in various colors. This included one bare wire that I'm sure is a ground (otherwise why is it bare?). I rewrapped this bundle up just to make sure it wasn't causing an issue touching something it shouldn't.

3rd I didn't have adequate time to fully explore how to gain access but the passenger presence module connector is blocked by the motor that moves the seat (my Suburban is an LTZ). I didn't see any obvious issues but could not get my fingers in there to give the connector the same treatment I did to the seatbelt clip.

I'll try again next weekend if I have more time and the weather cooperates. For now I'm still getting an occasional B0081 0f SRS dash light. I'm hoping that if I move the seat all the forward or back the motor will be out of the way enough to access the module connector to clean it. The module itself is riveted to the frame of the seat so I'm not excited about taking the leather off and drilling out rivets to replace the thing.