I got a Town and Country from a family member and fixed many things to get it in good shape, then before taking it to inspection realized that the airbag light is on (which would make it fail inspection in Virginia). I got SRS codes read for free the other week at a Carquest and got the following codes:

• "occupant classification undetermined"
• "occupant restraint controller status message missing"
• "override [sic] control module power source missing"
• "override [sic] control module data transfer error"

I believe "override control module" might actually be the "occupant control module" (OCM), the code reader maybe had the description wrong. In any event, the Carquest guy said it's as if something is unplugged, or the brain of the airbag system has gone bad. I checked all airbag system connections I could find (2 at the main computer in center console and all the ones under the seats), cleaned them with cleaning spray, dead-brained the system (battery unplug for a long time with + and - leads connected), and that didn't fix it.

After some other online research, it seemed like maybe the OCM module (under passenger seat) was bad, so I ordered one for about $30 on eBay and installed it. Still no fix. Maybe it's a stored code? So I bit the bullet and bought an OBDII reader that also does SRS and ABS codes for about $100. I went in and cleared the SRS codes ("power supply voltage low" was the only stored DTC), then proceeded to read any codes that might be active in the system. This is where things got weird...

Every time I read the codes, it was something different, between 1 and 3 codes each time. Here is an example of the active codes I read out, seemingly random every time:

• Passenger squib 1 short to ground
• Acm internal diag #2
• Cluster message mismatch
• Passenger seat belt tensioner circuit shorted
• Driver seat belt tensioner short to ground
• Driver side curtain or seat squib circuit short
• Internal 3
• Passenger squib 2 circuit open
• Driver squib 1 short to ground
• Driver squib 2 short to ground
• Passenger side curtain or seat squib circuit open
• Airbag warning indicator open

So on and so forth. They are not all active at once, every time I read they seem to be different. So what is going on here? Clearly not every single component simultaneously went bad, so I think I am back to square one -- that it's either a bad connection or the main computer is bad, but I would appreciate some other opinions before I buy the main airbag computer replacement. If it's a connection, where else should I check? I've read stories online of cables being pinched in the seat movement mechanisms, but I don't see evidence of that under either seat. Or is this definitely a sign that the main computer is bad, because it's just throwing every code in the book? Any help from those with experience in airbag system problems would be great. Thanks.

 

Whilst I'm not an expert in the SRS part of the system, I've had the odd fault popup on mine and luckily I did a connector waggle under the seats and solved it.

However, random faults showing different to me would start to suggest a damaged cable (I'd not be thinking the computer is bad as it's still giving you readings, and it's giving you the same 'group' of faults/readings, so it's brain seems to be functioning), so my thoughts would be to check the cable bundle under the seats as my guess is a wire is trapped or jammed and shorted to ground, or where the cables go through the bulkhead it's been rubbing and shorted.

Just a guess but from looking at that it would be my guess, do the codes change depending on if you move the seats forward and backwards, etc?

Hope you manage to track it down.

WARNING: Please don't use continuity test on the multimeter and test the wiring in place without disconnecting either end, setting an airbag off is not fun and can be deadly, they need a voltage to trigger so just pay attention!!

 

Thanks for the reply andyb2000. I like what you're thinking and I'm hoping it is a cable or a connector, because that would be relatively easy to fix. However I have looked under the seats and looked again and can't find anything noticeably wrong. Perhaps I will have to go ahead and unbolt the seats from below the vehicle to get a full view. At your suggestion, I did try moving the seats forward and back and could not find a configuration that produced a noticeable change in the DTC codes that came out of the system.

Any other suggestions out there for next steps?

 

THE ocm IS WHAT DETERMINES IF YOU HAVE A CHILD SMALL WOMAN OR 90LB OR OVER PERSON IN TEH PASSENGER SEAT THAT MODLE IS UNDER THE PASS SIDE SEAT.

 

Yes, I know. As I said in my original post, I replaced the OCM...

 

SRS(airbag) codes are pretty specific on most all vehicles. From codes you are posting, it sounds like harness damage and not connector problems. You said you did a lot of other work to get the van running, how badly torn up is the interior or possible rodent damage inside the vehicle. And did you make sure you got the correct for VIN OCM?

 

Good thoughts — no real interior damage, the work I did recently was like inner and outer tie rods, front and rear brakes, ignition coil, battery, etc. Don't see any evidence of rodents chewing cables. The only thing I did that may have interfered around SRS cables was replacing the blower motor, but that was really not too bad and I wasn't rough around the area. I talked to my aunt again recently (previous owner) and she indicated the SRS light may have been on for a couple years (apparently they knew some shop that would pass it anyway), so I don't think it was anything I did. I will have to dig around deeper to find signs of cable damage.

Did not do a specific check on VIN compatibility for OCM, but it looks exactly the same as the one I took out.

 

Not being able to "see" what is going on, I just had to offer from what info was given. Good luck in tracking things down and making all better again.

 

if you got a used one then wont work might be able to be programmed plus its use to the old calibration and weight from the old chair used not yours.

 

I've *heard* that if you unplug each of the harnesses under the front seats, slather the female plug with dielectric grease and replug them then a bunch of problems mysteriously disappear.