Aygo 2010 Blue Airbag Fault

[fossyant]

Hi All,

Looks like I have a garage visit to arrange.  The Aygo's airbag light came on in October a little after being on a slightly bumpy tarmac farm track and I cleared it at home (switched ignition on/off 7 times). This stayed off until early January, and since I've been checking all the connections, passenger, side impact and pre-tensioners, and liberally cleaning the connectors with contact cleaner. Even disconnecting the Battery, etc, the light always returns after a few minutes. Once or twice it's gone out mid journey, but it's been 'flashing' on the last two weeks. I've bought an Autel MaxiLink ML629 that can access the control units including the SRS - it says it can't connect to the SRS Unit, but has been able to check everything else. Only thing it found was something to do with rear speed sensors (doesn't have this on a 2010 aygo as no stability programme) and low Battery voltage in history(Battery is new six months ago as well as alternator). I cleared these and nothing has re-appeared (no warning lights previously).

It works fine on my Nissan with systems and SRS.  If it's saying it can't connect, I'm thinking I need to check the main connection's to the SRS control unit, which is located behind the cubby holes in the lower dash near the gear stick. I'll disconnect the battery, leave it a while and check and clean the connections. I can only think, there could be an issue here.

If that doesn't sort it, I suspect a garage has better equipment for diagnosing, but at least I can rule out corroded connectors.

If the battery issue pops up again (there have been no issues starting in the freezing cold), this might need checking. Battery might be an old stored code from when we had an alternator issue (months before the SRS light).

[Bper]

Hi Antony,

Have a look at this link it may help it mentions speed sensors.

https://www.700r4transmissionhq.com/toyota-aygo-airbag-light-on/

[DerekHa]

3 minutes ago, Bper said:

Hi Antony,

Have a look at this link it may help it mentions speed sensors.

https://www.700r4transmissionhq.com/toyota-aygo-airbag-light-on/

That's a very comprehensive, informative and interesting article you've turned up there Bob.👍

[fossyant]

Thanks - worth a look at those at the weekend - assuming it could be something to do with the rear sensors.

[fossyant]

Hmm, given how the previous owner didn't do much to the car (state of brakes and drums) - since sorted, I'll check for gummed up and corroded rear sensors. Might make some sense in that if the SRS is cleared, it comes on again after a few minutes drive. I cleared it last night with the reader (by clearing the battery/ rear speed sensor codes), popped out for a quick drive but within minutes it was back on. I'll read the codes again this evening. May be a job for the weekend.

[flash22]

Airbag main culprits are the yellow connectors under the front seats, does your horn work ?

i can't see the ABS being an issue you would get ABS codes, rear wheel bearings are part of the hub with the sensor in the back, its less stress in the long run to swap the hub

Rear hub

Eg. https://vehicleaftermarket.skf.com/uk/en/products/VKBA3697

 

[fossyant]

Horn works !   My local garage is good, but I know it could be expensive - I'd rather check the obvious. Seats checked too. It's got to be fixed as my daughter will be driving it once she passes her test (booked for April or May)

[flash22]

Manually pull the codes if any ? Have you updated the scan tool by connecting it to the PC and use the Maxi Pc Suite https://www.autel.com/u/cms/www/202211/040800364oh9.zip

 

If the Jolt you had was hard enough, the Yaw sensor in the SRS may have trigged a crash event - no codes logged, you will have to send the SRS ecu off to be reset

[fossyant]

I updated the Toyota files last night as I only just purchased it - my other reader doesn't do ABS. It has connected to the other systems fine, other than ABS, which it said couldn't connect.  I'll have a good poke about with the contact cleaner (it's certainly fixed airbag issues on my Nissan). 

The jolt wasn't that much, and it did clear for two months. I'll check all the connectors and that they are clean, and if not, my local garage will be getting some business. My son is rather handy as he's changed the engine twice in his fabia and the associated electrical issues but, as you say if it's triggered a crash then it may need a reset.  We've had the car a year, and there was a small amount of paintwork damage on the front bumper, but the garage fixed that before we picked it up (most used Aygo's seem to be scraped).  

It's just odd the Autel isn't accessing the one SRS ECU when it can the rest of then car !

[flash22]

It may even be a clockspring issue being intermittent, you could try techstream with a mini vci

[fossyant]

Does anyone know where the left and right front impact sensors are located. I've traced a couple of wires but they seem to plug into somthing that can only be accessed if the bumper is removed (near the lights) - could feel something on the passenger side, but waterbottle in way on driver's side.  I've fiddled with it and the airbag light has gone off. I've done a couple of test rides and it's "off" at the moment. Booked in for the 14th, but if it's behind the bumper, I'll whizz that off and give the connectors a good clean.

I couldn't see anything on the engine bay walls.

[fossyant]

Just shuffled the car onto the drive with lots of steering lock and the light is still off. Must use the car this week to see how it goes, then postpone the garage visit.

 

It did have a new clutch a few weeks before the light went on so wether the garage disturbed a wire we don't know. Assuming Battery tray had to come out there is a major loom near it.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[flash22]

The system doesn't use front impact sensors, so what does it come up with when you try to connect to the srs ?

[fossyant]

Still unable to connect with the Autel reader - just says can't make a connection to the SRS module - the other modules connect (ECU and ABS).  Light has come on again, so it's looking like the clock spring maybe. I'd be fine if I could pull a code, but can't. My son's just changed his clock spring on his Fabia this weekend.   

Glad to hear I'm not looking for additional sensors in the Mk1

[flash22]

i take it you have unplugged and re-pluged the SRS module

[fossyant]

Thanks @flash22, I did indeed unplug, contact clean and plug the SRS Control module back in, but didn't think to re-scan. Got home tnight, plugged in the reader, bingo. It's the clock spring/squib - looks like an intermittant fault so I'll replace it. Off to see ebay/motor factors for best price.  Car electrics are very strange.

On my car, if one of the rear lamp connections get's damp (I don't use it much) I get an intermittant misfire. It's due to the fuel pump's earth using the same loom as the rear lights ! Madness.

[flash22]

The Aygo is well known for leaking around the rear light seals, nothing new there

[fossyant]

Meant to add my car is a Nissan. The Aygo is son/daughter's car - mainly daughters for when she passes her test. Fixed the Aygo leaky boot though.

[fossyant]

All fixed. Used clock spring part arrived today - £35 with next day postage. 40 minutes start to finish including getting tools out and putting away. Phew.

 

Thanks for the ideas with disconnecting the control unit to get the code.

[fossyant]

Issue returned about 10 days later. Tried another clock spring, still flashing. As the ODBC still wasnt connecting, ordered a replacement SRS ECU. Fixed. Looks like the original had gone wonky.