To provide a bit of insight. The alternator/battery in the car charge a capacitor in the SRS system, which stores power to operate the airbag for probably no more than 10-20 seconds. This is so that in an accident, the airbag will work even if the battery and alternator are inoperable ie the airbag system will have its own power. This is only needed for a short period of time since the time frame of a crash is at most a second or so.
Once the battery is disconnected, the capacitor discharges slowly. Not sure if that is from its own internal resistance, or the system has a bleed resistor.

Persistence pays off....finally was able to get a fault code. It was a -1- indicating a faulty crash sensor or connections. After disconnecting the battery negative cable, I checked the connections. All seems well with them, but the SRS remains on. So....now to find a good used crash sensor. Anyone have a good one to spare that will work on a 93 240? Daryl

No progress yet. I tried exactly as recommended in the FAQ: 1. Turned on ignition switch to position II for 15+ seconds. 2. Jumper wired SRS terminal behind SRS blank in center dash switch panel to lighter ground ring for 2 seconds 3. Waited for code to register on SRS light in main instrument light display, but nothing. When jumper was disconnected, the SRS light returned and stayed on steady without interruption. 4. Tried to reset 3 times by shorting to ground for 1/4 second 3X over 3 seconds. 5. Everything is unchanged. Light still on.

Are we ready for the battery 1/2 hour disconnect....or what should I try next?

Daryl

I had a symptom in which the SRS light was on for about 30 seconds after start and then would go off.

Shortly after that began, I noticed all the dash lights had an extreamly low glow with a slight flicker. I noticed this miles away from the city very late at night with cluster lights low. Turned the cluster lights up full and could not see any glow they were that dim.

Checked battery charging rate which was at low end of range. Replaced alternator regulator because of short brushes and the SRS on for a short period of time also went away.

I'm not sure, but since the SRS system needs a constant charge to keep the firing charge full**, if the battery is not charging properly or the battery is weak using all the charge put out by the alternator, the SRS would probably indicate a problem. At least that's what I dervied. The Service Techs at the local dealer wouldn't/couldn't confirm if deduction was correct.

** supposedly waiting 30 seconds after disconnecting the battery will prevent?? the bag from exploding to me indicates a circuit that bleeds off its charge.

And since the circuit needs a ground, that ground should also be checked from a safe location which is not near the bag deployment area. It may be prudent to wait longer than the 30 seconds to check the ground since the system probably bleeds off through that ground.

Duane

SRS test port on 240 is not linked to engine bay OBD. it's on the center console next to window defroster/emergency light/AC switches. you have to pry off a cover piece to see the connector.