SRS Airbag Service Urgent

[kdst5]

While driving had "SRS Airbag Service Urgent" pop up on the dash. I have tried to clear the fault with VIDA but it won't clear. These are the codes I have after trying to reset them:

DDM-B119100 Right rear window
PDM-B119000 Left rear window
DDM-8118F00 Right front window
PBM-U015100 Lost communication with supplemental restraint system module
PDM-8118E00 Left front window
CEM-B10A202 Crash input - general signal failure
CEM-B10A215 Crash input - general electrical failures - circuit short to battery or open
CEM-U015100 Lost communication with supplemental restraint system module

I have taken the SRS module out to have a look, there is no obvious damage. There is a suggestion on here that it could be related to the seat belt recall which, I had done last year, see here https://www.volvoforums.org.uk/showt...=310745&page=3

In the network view of VIDA the SRS module is red where as the CEM, PDM & DDM are green.

Car is a V70 Lux D5 2014-2015

Does anyone have any ideas?

[Simmy]

delete codes rescan and read only the delivery tab. not the initial state. tab crash module faults show up as a hddd code . try watching a quick guide to Vida by Mathew leavsley on you tube. you need to look at each individual fault in vida . its much more than a code reader its a full diagnostic tool .far too complicated to explain in a forum post.

[kdst5]

The list of codes were from the delivery tab after a delete and rescan. I have been in to the other modules listed on the codes and can get values from Vida for them but can't get a single value out of any on the SRS module. Will have a look at the YouTube you suggested.

[Simmy]

click on the srs fault and use the advanced tab to narrow it down further it might also be worth joining the volvo vida users group on face book for some help.

[kdst5]

The main SRS test show it can't communicate with the module. It also says that there are 2 power feeds to the module and provided either feed has power then the SRS will work. I can only conclude that the module has died.

[Clan]

Originally Posted by kdst5

The main SRS test show it can't communicate with the module. It also says that there are 2 power feeds to the module and provided either feed has power then the SRS will work. I can only conclude that the module has died.

Has the module got those live feeds and is the earth lead ok? Next you need to check the network output and input signals on an oscilloscope . Be careful dabbling with wires down there could set off air bags !

[kdst5]

The fact you could set off the air bags makes me nervous which could turn a bad day with the SRS fault into a very bad day and a very expensive repair.

I obviously don't have the breakout box and the pins in the socket are thin and exposed. I have check the fuse 18 in the glovebox is OK and there is power on the input to the fuse.

Fuse.jpg

I presume I have the correct fuse? Does the output of this go straight to the SRS module behind the gear lever or does it go via say the seats first?

Am I correct the earth is via the case? In which case I have measured the resistance between the case and the body of the car.

From what I can tell the power to the SRS module in on the smaller of the 2 connectors and is pin 42 and 43 am I correct?

Clan in your experience do you have any idea of the likely hood that the module is dead and just needs to be replaced?

I have also opened up the module to have a look and see if any of the components show signs of damage which they don't. The only odd thing is the pins for the connectors are not soldered to the board but look like some sort of very tight push fit. My thought was could one of these have a bit of tarnish on it which would then cause high resistance. Have to say I was surprised they were not soldered.

[Simmy]

send it to crash data in Liverpool. they can test and repair crash modules . iv had a couple of units repaired . if you book a time and exact date they may be able to do it same day. otherwise its post it and wait a couple of day for the outcome dependant on postal strikes. new units are expensive from Volvo that's why crash data repairs hundreds of units.

[kdst5]

Yes I had thought about sending it to crash data. I am in the south east so it will have to be posted to them. I think I should just confirm there is power on the connector first, just want to be very carful about this so not to make a mistake.

[Clan]

Originally Posted by kdst5

The fact you could set off the air bags makes me nervous which could turn a bad day with the SRS fault into a very bad day and a very expensive repair.

I obviously don't have the breakout box and the pins in the socket are thin and exposed. I have check the fuse 18 in the glovebox is OK and there is power on the input to the fuse.

Attachment 145865

I presume I have the correct fuse? Does the output of this go straight to the SRS module behind the gear lever or does it go via say the seats first?

Am I correct the earth is via the case? In which case I have measured the resistance between the case and the body of the car.

From what I can tell the power to the SRS module in on the smaller of the 2 connectors and is pin 42 and 43 am I correct?

Clan in your experience do you have any idea of the likely hood that the module is dead and just needs to be replaced?

I have also opened up the module to have a look and see if any of the components show signs of damage which they don't. The only odd thing is the pins for the connectors are not soldered to the board but look like some sort of very tight push fit. My thought was could one of these have a bit of tarnish on it which would then cause high resistance. Have to say I was surprised they were not soldered.

yes pin 42 and 43 are the live inputs

Yes the earth is the case directly screwed to the chassis, they don't get better than that.

yes the 2 power wires go direct to the fuse.

The only SRS control units I have changed have had the code for "Internal fault " mainly on the older V50/S40/C30



soldering has proved not to be too reliable long term in cars due to the extreme temperature changes over many years causing cracks at the joints. , hence problems with instrument panels, and CEMs after the car gets old, the SRS unit can afford to have a better more reliable system.

You need to be very careful with these units when powered up, never remove them with the plugs in, the vibration could set off all the air bags.