SRS light on

Pscan test on airbag error code 150C
Continuity test from dcu block connector to rotary coupling connector ok
Continuity from rotary coupling input to output onto drivers airbag connector ok
Continuity from dcu block connector straight through to drivers airbag connector ok
Continuity  through connectors under both seats to pre tensioners ok
Continuity from dcu block connector to both passenger airbag connectors ok
I have tried a different drivers airbag and both seat pre tensioners these made no difference they were second hand.
When connectors are made open circuit they always clear and leave the error code 150C
Any Ideas
Regards
PBR73
 

Have you measured resistance values you get from DCU block connector to drivers airbag connector?
150C means Front airbag circuit drivers High resistance. Continuity is not in question here, but what resistance values you get.
 

I did test on resistance setting, meter set at 2k I called it continuity.
The resistance reading between dcu block connector and drivers airbag connector 0.000 to 0.002.
What i failed to understand is, if i put one probe into one side of the airbag and the other probe into either side of the dcu multiplug connector i get reading from both pins, then if i move the probe into the other pin on the airbag connector and then check both pins in the dcu connector, again i get a reading from both pins.
I'm not a electrician.
The other tests i did also had results from 0.000 to 0.006.
I redone the test today on the dcu block connector to drivers airbag connector same results, I also did the test on full left and full right lock to try and check the rotary coupling again same results.
Thanks for the reply.
Regards
Pete.

You should not have connection on both pins on one side. That is cross connection somewhere. This might be your problem.
I would inspect dcu block connector and check that you do not have some part of wire within the connector terminal touching another terminal and because of that you ahve such cross connection.

What i failed to say is the same thing happens when i test any part of the block connector, that is, the two connectors in the block for the two leads going to the passenger airbag, and the two connections in the block for the two seat pretensioners. Can one wire cause the same problem across the block.
Have you ever opened up one of these block connectors, I'm wondering do they fall apart/break and do they ever go back together.
Don't know what the chances are of finding a new block.
Regards
Pete.

Can you post a picture of the connector where you get connection on both pins, showing pins?

Since in all cases you mention pins on connector block on DCU side are neighbouring ones, are you sure you are not touching two pins at same time with the probe?

You can put the probe into the two small square holes under the oblong hole and get the same reading without moving the probe at the airbag connector.
Also you can put the probe into the oblong hole above the two small holes and get the same reading.
The drivers airbag connector is the first oblong hole past the six small square holes.
Regards
Pete.

 

 

If you get same reading in oblong hole below/above (depends how you look at the picture) two small holes which are for drivers airbag I suspect that probe went too deep and is actualy touching another pin/terminal within the connector. 

In this case I would just discard this as irrelevant since it is not a way how to address your problem.

Have you checked that you do not have corrosion on the terminals on the DCU itself?

To me this error seems like you have open circuit on drivers airbag connection. You said that you tried another second hand drivers airbag - was that identical airbag from same car model year? If nothing else help, then maybe another DCU should be put into your car? However, if you go into route of another DCU, you must be certain that another DCU have same setup as your car - for only one driver airbag, or if you have passenger airbag, then for both. Otherwise DCU will again throw error.

EDIT: You can also try to see - measure - what resistance you have on airbag, and 2nd hand one too. I am expecting to see some 2.2 ohms, if I am not mistaken.

  Hi, I'm back on the F, rechecked readings but with probes barely touching pins on the dcu multiplug and drivers airbag connector same result.
There isn't any corrosion on the dcu connectors or the multiplug connector.
The other airbag i tried was the same. I sourced it from mgfntfbitz so it should be good
The readings on the photo are with the dcu dis-connected and the probes either side the airbag connector I also did this test with the rotary coupling disconnected and got the same result. I saw this test online so think my coupling is ok.
I haven't done an airbag airbag test, not sure how to, I've read they can go off doing the test witn a multimeter.
My F has a passenger airbag, difficult to find a good known one and expensive to buy new if not sure it will fix the problem.
I've thought for a while it was the coupler or dcu but it looks like the coupler is ok, but still nor sure on thr dcu.
Regards
Pete.

 

Have you retrofitted the passenger airbag? The controller has to be the correct one for the airbags to be recognised & the warning light extinguished.
A very short time ago there was a glut of both drivers & passenger airbags, both new & unopened in OEM packaging.
I bought one of each & spare controller as a hedge against the possibility of future failures.
I can’t find references to the passenger airbag cost but the drivers cost £15. There was little difference in cost.
M

You should not get that kind of reading on your multimeter. If probes were barely touching terminals, then you have some shorting on lines somewhere. In thins case even new DCU would not help. Wiring seems to be the problem. Rotary coupler usualy breaks the line, not make shorting.

Hi Roverlike,
Thanks for the help, i just wanted to say when i first took the resistance readings it was with 2mm probes and they had to be pushed hard lnto the connectors to get a reading.
I then bought 1mm probes and this made it easier to take the readings, both sets of readings were the same.
So when i say barley touching, the probes are well into the connectors but not pushed through to far.
I have taken the coupler off the vehicle again and resistance seems ok.
I have taken a couple of photo's of the coupler, the pins are separate where the block connector fits on, but then the metal is folded over and it is joined together.
Like i said I'm no electrician but i don't understand this.
Thanks again
Pete.