SRS light and no comm to the SRS module

wheezy · Post by **wheezy** » 25 Dec 2011, 21:25

Hello everyone! I'm a Volvo and forum n00b, so please be patient with me.

I bought a 2000 V70 XC AWD. The SRS light comes on during the bulb test as it should, goes off for a split second after the car starts, and stays on as long as the car runs. To troubleshoot the issue, I grabbed my Autel Maxidiag US703, loaded the Volvo.zip file, and connected it to the car. I can see the engine computer, transmission, etc. but it can't find the SRS module (basically a module not found message). The local Volvo dealer could not reset the code either and said they would need to talk to Volvo tech support because they could not troubleshoot the problem. Since it was a Saturday morning, no one was available from Volvo. I can only assume that they could not see the module either (I don't know for sure, they did not tell me why). The guy I bought the car from said that it came on when he removed the radio to take out a jammed tape. When he put the radio back in, the light came on and has been on ever since. I pulled the radio back out and there were no connectors that seem to be apart behind the radio.

I'm a little baffled. Does anyone have a suggestion of where should I start looking?

I know the SRS module is in the center console and is relatively easy to get to. I found a donor module from a similar (not crashed) car that I can get for about $35 at a local auto recycler. Is it worth a shot to just replace the module? Can these modules be moved from one car to another without being reprogrammed?

Sorry for having more questions than answers.

Thanks in advance for your input.

Post by **Ozark Lee** » 26 Dec 2011, 07:03

I don't think the US703 will read the SRS codes beyond Ford, GM, or Chrysler. The EU702 should read them though.

...Lee

Post by **Matty Moo** » 26 Dec 2011, 07:51

The eu702 will, not that it does you any good at this point. I was playing with it the other day and it picks up the module on our s70, tells you the sn#, read/erase codes, etc.

wheezy · Post by **wheezy** » 26 Dec 2011, 15:01

The only difference between the JP701, EU702, US703, and the FR704 are the brand files that are loaded into the flash memory. Since there is spare flash space, I added them all but the Benz files (that one wouldn't fit - it's huge compared to the others).

If the EU702 works to read/reset SRS, mine will also. It sounds to me line the module might be dead or somehow disconnected. All of the connections look OK, so I guess the module gets swapped out next.

Does anyone know if the thing is VIN sensitive? Will a module from another car work without reprogramming?

Thanks!

Post by **Matty Moo** » 26 Dec 2011, 19:36

I know most of the other modules on the 99-2000 aren't vin-mated, unlike the 2001's.

If you don't mind me asking, could you point me in the direction of the us703 flash files?

Post by **jimmy57** » 26 Dec 2011, 20:03

The Instrument cluster (CDM ON THAT CAR) controls light and it is default on. IF the CDM gets no command from SRS then the light comes on light you are seeing.
Before you give up on SRS be sure alternator is good. Proper charge voltage and no excess AC (<100mV AC).

wheezy · Post by **wheezy** » 27 Dec 2011, 07:09

@jimmy - Good idea, I'll drag the scope out and take a quick look. The dealer checked the alternator when they replaced the battery for me (they couldn't program new keys because it was low), but who knows if they checked for ripple or picket fencing. Probably not...

@Matty - I zipped up the files and put them here: http://www.megaupload.com/?d=Y5696TQ1
You use the PC-Link program to reflash the unit. I included that also. You can't fit all of the files on one scanner, but you can get most of them on there. I got mine cheap ($135) and it works pretty well.

Thanks for the advice. It might be a few days before I can back to this car, but I'll close the loop.

Post by **JRL** » 27 Dec 2011, 08:12

It also could be as simple as a reset at the Volvo dealer
Someone could have removed a seat without disconnecting the battery

wheezy · Post by **wheezy** » 27 Dec 2011, 08:28

The dealer could not read/reset the code either. That's the problem.

wheezy · Post by **wheezy** » 28 Dec 2011, 08:28

I dragged out my old Leader scope, set the coupling to AC (to get rid of the DC component of the signal), connected the probe to the fuse powering the SRS module. Tested with headlights, rear defogger, and blower motor on high. Ripple varies from 20-50mV depending on the RPM of the engine. There were no spikes bigger than about 50mV visible. I wish my GM alternators were this clean.

I'm going to purchase the used SRS module as the next step.