Persistent passenger occupancy mat SRS warning- even with an emulator

[typed by ben]

Good morning all,

I am polishing up a 1995 M3 that I bought in November to get it ready for state safety inspection. It won't pass with the airbag light illuminated after engine start. I broke down and contacted a local garage last night but this morning I am back to my senses.

I have been having a hell of a time getting an SRS warning light to go away. When I bought the car the owner stated the airbag light stayed on- no big deal (as all big deals start out), I'll fix the problem and reset it. I bought the Peake Research R5/SRS tool and scanned the car getting a table 01 fault 14 warning, seat occupancy mat. Reset it then and it stayed off for a couple of days, but only for what may have been 20 minutes of engine run time. Then it came back. I bought a seat occupancy emulator from eBay and installed it, thinking that would at least get me through inspection until I have the time to get a new mat and put it in. Installed the emulator, reset with Peake tool, no change. Airbag light still on in dash, still reading table 01 fault 14.

I plugged the occupancy mat and tried to reset. No change, same fault.

I unplugged EVERYTHING going to the underseat module to see if it would recognize that nothing was actually plugged in, and I at least get a second fault, this time table 01 fault 14 and table 01 fault 19 for the seat buckle. That checks out. We are changing states.

Now, the SRS module won't reset the table 01 fault 14 code at all. Every time I scan I get the same error, table 01 fault 14. The Peake tool thinks it has cleared the fault but the light on the dash says otherwise. You can scan and reset for eternity. Has anyone experienced that same problem? I would like to troubleshoot this instead of throwing money at it. I am halfway decent with a meter but I just can't find anything in the wiring or plugs that would make the same fault appear, regardless of the disposition of the sensor that should send it.

Do the underseat modules go bad? Am I looking at replacing the SRS module under the dash? Should I disconnect the battery and do a European reset for all the car's modules and try again?

[kevinwilly]

Just grab a new under seat sensor and dash module at a junk yard and replace them both. it'll probably be like 20 bucks total. Not worth the time trying to figure out what is going on in my opinion. You've almost certainly got a failed module. Or a cut wire.

[typed by ben]

Just grab a new under seat sensor and dash module at a junk yard and replace them both. it'll probably be like 20 bucks total. Not worth the time trying to figure out what is going on in my opinion. You've almost certainly got a failed module. Or a cut wire.

That's the way I'm leaning too if this battery reset doesn't work. Do I need to match hardware and firmware numbers?

The local garage guy got back to me and said right off the bat "be prepared to spend several hundred dollars in diagnostic fees." No thanks!

[typed by ben]

Ordered a new underseat module. Fingers crossed. The under dash module I think is a non starter as it will have to be coded and I have no resource for that short of a dealership.

[AJLM34A]

Ordered a new underseat module. Fingers crossed. The under dash module I think is a non starter as it will have to be coded and I have no resource for that short of a dealership.

A 1995 does not have an underseat module or under dash module. The crash control module is under the back seat, seat bottom. Did you check the fuse and the ws/rt wire to see if it has continuity?


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[typed by ben]

A 1995 does not have an underseat module or under dash module. The crash control module is under the back seat, seat bottom. Did you check the fuse and the ws/rt wire to see if it has continuity?


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i must have a bit of a rando then. I have this underseat module which accepts inputs from the seat occupancy sensor and the passenger seat belt receiver:



I was just under the seat replacing the fuel pump assembly and don't recall an electric module back there. I will check that this evening. The fuse is good, first thing I checked. WS/RT I'm guessing is white red. I'll check for that as well. I just found the E36 Bentley upload which has been somewhat helpful.

[AJLM34A]

The ETMs show 1998 is the first year of the module but the part number shows a much larger production range.

The SRS module is metallic flat and square in the center of the seat bottom area.

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[typed by ben]

The ETMs show 1998 is the first year of the module but the part number shows a much larger production range.

The SRS module is metallic flat and square in the center of the seat bottom area.

Screen Shot 2017-01-16 at 3.50.58 PM.pngScreen Shot 2017-01-16 at 3.48.13 PM.pngScreen Shot 2017-01-16 at 3.45.43 PM.pngScreen Shot 2017-01-16 at 3.42.20 PM.png

Go figure on that one. You are correct about the SRS control module under the seat. Just didn't notice it. And interestingly I have been doing work in that area, though the light as been on since I got the car. I will do some more wire troubleshooting later tonight and update. Thanks for your help.

[typed by ben]

Everything toned out to the under seat module. Has to be one of the modules at this point- or the emulator is a big old POS.

[Pyropete82]

Had the exact same issue. Code finds seat occupancy sensor fail. Tried to bypass with the under seat module as well, same failure after cleared. Concluded it's the mat, wires crossed or something due to folding seat back and forth? Anyhow gave me reason to go to momo steering wheel and toss the bulky 4 spoke.

[typed by ben]

Had the exact same issue. Code finds seat occupancy sensor fail. Tried to bypass with the under seat module as well, same failure after cleared. Concluded it's the mat, wires crossed or something due to folding seat back and forth? Anyhow gave me reason to go to momo steering wheel and toss the bulky 4 spoke.

so what did you end up doing? Just lived with it? Unfortunately that is not an option for me, as the airbag light has to be out for annual safety inspection.

[Pyropete82]

Ah, didn't know. Interesting, is that for tracking the car or are you using it for commercial transportation? Anyhow, just lived with it, still living with it. Like another said, you are better off grabbing a working occupancy mat and trying that. You can also delete the airbag with INPA for the passenger side, but anyone with diagnostic software will see it's missing on a scan. Your driver side may also be affected, so keep that in mind.

[typed by ben]

Ah, didn't know. Interesting, is that for tracking the car or are you using it for commercial transportation? Anyhow, just lived with it, still living with it. Like another said, you are better off grabbing a working occupancy mat and trying that. You can also delete the airbag with INPA for the passenger side, but anyone with diagnostic software will see it's missing on a scan. Your driver side may also be affected, so keep that in mind.

It's a state requirement where I live. What bothers me about just throwing a mat at it is that the emulator SHOULD... well... emulate the mat's presence and eliminate that as a fault. It doesn't.

As for INPA, I was unaware you could use INPA on a 95. That would actually be my preference because I could disable it for inspection then enable, at least until I get to the root cause of the problem. The light doesn't bother me, just keeps the inspector from giving me a new sticker.

[AJLM34A]

Does VA check to see if the cluster shows an SRS light when the ignition is first turned on? If not, take the bulb out of the cluster.

[typed by ben]

Does VA check to see if the cluster shows an SRS light when the ignition is first turned on? If not, take the bulb out of the cluster.

I'm sure some do and some don't. The first guy caught that it stayed on and then timed out and failed it on that account. Can't go back to him if I just take out the bulb because he will be looking for the self test on startup.

[AJLM34A]

I would look for a good used module in the car part out section or a local BMW used part place.

[typed by ben]

I would look for a good used module in the car part out section or a local BMW used part place.

I have read that you need to code a new module to your car. I had to do that with the LCM on my '97 540, but I don't have the hardware I need (I believe it's a cable/comm bus I don't have) to do that- at the moment. If it comes down to that I guess I will need to go to INPA on a '95 University.

- - - Updated - - -

My under seat module arrived today so I just installed it with the emulator.

Forgot to plug the crash detection sensor back in after I rung it out so of course I had a big problem at first. After I realized that, I plugged it back in and got the seatbelt buckle and occupancy mat errors again. "Here we go again," I thought. I cleared the codes with the Peake R5/SRS anyway and much to my surprise they have not come back. I will update this thread if anything changes.

I read in multiple places that those under seat modules don't go bad and very few people report trouble with them, but they are sold by most vendors around the web. That told me it wasn't an impossibility. Thank goodness I didn't use the shop that warned me of "several hundred dollars in diagnostic expenses" in an e-mail.

Thanks to all for their help!

[DocWyte]

Where is the underseat module located? I got my emulator, moved my passenger race seat forward but don't see a little black box like you have pictured?

[shogun]

Maybe this helps, pics https://www.bimmerforums.com/forum/s...-sensor-bypass

[DocWyte]

Couldn't find it because it wasn't there! Checked my stock seats in my basement to see if it was there, nope. Started digging through my boxes of stuff and I ended up finding it, along with another occupancy mat, a set of 15mm Turner spacers and the spring loaded hardware bits for my Motion splitter.

Score!