Airbag light is on with two codes:  Control Module and Seat belt pretensioner.

61 (Seat Belt Pretensioner R Side Circuit Open, Short, Short to Ground)
25 (Air Bag Control Module is Faulty)

I disconnected and reconnected the seat belt connector with no change.  My plan now is to:

1.  Check continuity of Selt Belt pretensioner ground wire
2.  Replace control module

Anything else I could do to test or determine if the computer is actually bad?

I bought this car salvage/totaled and rebuilt it, including replacing the this pretensioner and the control moduel - many years and 100,000 miles ago with no issues since then.

The SRS system is relatively straight forward in its design on the Subarus. I would actually compare the left side to the right side and see if there is a difference. It is possible the fault is not the pretensioner but the control module.

Compare left and right, meaning what difference would I look for?  You mean regarding electrical testing or the actual components?

I would compare the left and right pre tensioner continuity. Is this the 96?

ah ha - right 2002 H6, and good call, comparing sides wasn't crossing my mind.

 

*I guess I need to access the computer and test continuity to that connector?

*Or can I test continuity to ground via battery terminal/ground point? 

 

2001...maybe 2000...was the first year of pre-tensioner seat belts for Subarus and I think until 04 only came in H6's.

From what I am reading, a possible fault here is the control module itself. This can throw both codes. I have never seen a pretensioner go bad, but have seen (well read/heard) about the control modules ocassionally going bad. Since the pretensioner works off a signal coming from the controller, I would start by replacing the controller you may luck out. Anything more then that starts talking about test harnesses

http://ken-gilbert.com/wrx/STi_Manual/  This is for an STI but as we know Subaru doesnt really change things much even as they add features, they just build on a previous version.

Don't try to check continuity of the pretensioner! That will almost certainly set it off! The wiring leading to the tensioner can be checked but make sure the pretensioner is unplugged, and the battery has been unhooked and the airbag module discharged. You also need to unplug the airbag module connector, and you really should unplug both airbag inflator modules, and any other airbags or pretensioners so you dont accidentally set those off while poking around the airbag connector with an ohmmeter. But If you're very careful, and make sure the wire colors for the circuit match up at each end, you can usually test one circuit without having to go through and unplug everything.

 

An easy test might be to make a dummy resistor to put in the pretensioner plug to see if the code goes away. For this you do need to know the resistance of the pretensioner test plug, which you can probably find in the service manual.

possibility of mimmicking pretensioner noted.

indeed, i meant testing body side continuity, with pretensioner unplugged!

I figured that's what you meant but just wanted to make sure! Airbags don't go off randomly, They go off when you touch the wrong wire!

 

But thinking about this, power and ground, (especially a good ground), are very important for the airbag system. It would be a good idea to check voltage drop on the supply wires to the module, and check voltage drop on the ground to make sure its getting the proper supply voltage and the ground is good.

Will do.

 

Oddly - when attempting to read code, clear code and see which one came back first, I noticed the AIRBAG light very lightly fluctuating when both pins were inserted (to presumably clear the codes).  So faintly that sometimes you could only tell by looking from the side, yet looknig straight on that affect was indiscernible.  I just wrote it off since it only did it with both pins plugged in...

It doesn't take much voltage variation to make those little warning lights dim. That could just be an effect of voltage drops within the module as it switches currents across the various memory circuits in order to clear them.

thanks, i'll ignore that. 

 

be home tomorrow where i'll have electrical testing supplies and contacted someone about a computer.

Does this by any chance have the overhead map light/warning module. My 05 OB had a similar problem and it turned out to be some electrical gremlin in there giving false readings. Replaced unit, 2 screws 2 connectors $85(IIRC) out of pocket, and problem solved.

Edited December 22, 201411 yr by brus brother

Thanks for checking but no, that's 05+ models.  That's such a weird one.

Gary did you determine what the issue was with your airbag? The light in One of my 97's just came on. From what I read could be as simple as a loose connection.

 

Were you able to access the codes via the obd II interface?

No airbag codes via OBD2 on that year.

 

Have to pull them manually, but the process is easy. Find the small black 6 pin plug under the dash, and there are two ground spades taped into the harness for that plug. Plug one of those grounds into a pin in the plug, and turn the key on, then the SRS light will blink the codes. I don't remember which pin it is off-hand, but you should be able to find it by searching for how to pull SRS/Airbag codes.

 

Does your horn button work? Does the cruise control work? Common cause for an airbag light is a bad clockspring behind the steering wheel. Often the cruise or horn will stop working sometime around the same time the airbag light comes on.

thanks.  Yes, both the horn and cruise are working at the moment.  I'll take a look tomorrow and see if I can pull the code(s) as you described.

Gary did you determine what the issue was with your airbag? The light in One of my 97's just came on. From what I read could be as simple as a loose connection.

 

Were you able to access the codes via the obd II interface?

 

You can't get the codes via the OBDII interface - but like they said it's really easy.

 

Yes - i found the issue.  A rodent (mouse i presume) had chewed through the wiring under the passengers side seat carpeting.   Spliced in some new wire and everything is back to normal.

Didn't get a chance to pull the codes but the horn and the cruise were inoperable today.  Weird they worked yesterday..

 

Anyway looks like the clock spring, huh?  Found a used one from a 97 Legacy.  Do you think it would be the same part for the Impreza?

impreza and legacy steering wheels differ and i suspect clocksprings as well.  that part is so easy to find and cheap that you should easily be able to find an impreza one if you can't confirm:

www.car-part.com

ebay

To close the loop, this ended up being the clock spring.  Was able to find a used one for $40.  Installed it and no more "air bag" light.

 

thanks again for the help