SRS Light

[Fred Byrne]

I was tidying the car and removed some cottonwool wadding that the previous owner had put under the left front seat. The SRS light came on afterwards. I put the wadding back and the light went out but after a few miles it lit again. I removed the front seat securing bolts and tipped the seat back so that I could get at the plugs. I wiggled and waggled the plugs . Cleaned them with switch cleaner but no joy. I then removed the yellow plug and soldered the wires. Still no joy.TOAF gives the following readings.

9134- Side Sensor; communication error
9035- Ignition Circuit IC4 sidebag front seat left resistance low
9132- Side sensor left plausibility error
9036 Ignition circuit IC4 sidebag front seat resistance high
9015 ignition circuit seat pretension left resistance too low

The only plugs I touched were the yellow and blue ones and I replaced the yellow plug with soldered joints. Can there be a polarity issue in the case of the yellow plug soldered connection? but both leads have the same colour coding.
Does the fact that the seat is tilted backwards at about 45 degrees matter? Or does the system require time to reset the codes? Hope some kind person can enlighten me please

Fred

[vitesse]

Isn't the side sensor the under the carpet one?

Regards

[Fred Byrne]

I think that is correct but I cannot understand why this sensor should fail in co-incidence with for example the seat belt tensioner. I' ll disconnect the sensor plugs and clean them but I'm not hopeful. Many thanks for your reply.

Fred

[ADO282]

I seem to recall the sensors on the early cars fail after being wet for prolonged periods.


When I removed the carpets from my car, although the carpets appeared to be dry, the foam stuff was sodden underneath.


The water had been coming in from around the big tube thing under the rear seat, which had a rusted hole in it.


When the garage read the fault codes on my car, the only thing coming up was the seatbelt tensioner circuit, which was due to a corroded connector, which has been replaced, so I consider myself to have dodged a bullet in that respect.


I'm sure some of the more experienced hands will come up with a detailed explanation for you.


Chris.

[Fred Byrne]

I am now down to two interconnected errors, namely;
Side sensorcommunication failure
side sensor plausibility error

I don't know what a plausibility error is. Anybody know? Anyway sometime soon I'll get round to this problem again. MOT always appears on the horizon very suddenly and unexpectedly so must not delay too long
Fred

[Mike Noc]

A plausibility error is when the ECU's detect a response that isn't what is expected, but there isn't a known error condition to put it down to. For example with an ABS sensor, if some magnetic reluctor segments are missing in the wheel bearing when they pass the sensor the ECU will activate the ABS on that wheel at slow speeds because it thinks the wheel is locking up, as that is exactly what the sensor sees, or rather doesn't see, when the wheel actually does lock up. But if it keeps seeing the same wheel locking up when none of the others are then that isn't plausible, so it alarms a plausibility fault.

If you sort the sensor communicaion failure then more than likely the plausibility error will disappear too.

[t5tart]

having just sorted out my SRS I can tell you yes polarity matters .. even though technically it doesnt I had the pretensioner code high resistence (after changing the ecu what a job)

the pre tensioner is the blue plug the airbag the yellow plug I did them with bullet connectors so I can a) remove the seat b) switch the polarity easily

the sensor is under the carpet (green or orange type) on the rail just forward of the rear seat mounts for the green type on the inner cill for the orange type


looking at your codes you need to do away with both under seat plugs asnd get another side impact sensor to test it

it only took me 2 days of head scratching and the interioor out to fix mine

to save confusion on the pre tensioner and the side airbag I put the female connectors one side and males the other and vise versa on the other plug that way they cannot be crossed over (if you plug the pretensioner into the airbag wiring and you get a fault it will point you to the wrong component )

so airbag side both femle on the car side both male on the airbag .. so polarity can be switched .. and the opposite on the pretensioner


dont forget to clear your codes when you make any changes to check .. I made that mistake thinking they would auto clear and re did wiring twice

[Fred Byrne]

I shall purchase a new side impact sensor. It won't break the bank. I guess that the problem is most likely the plug that supplies the impact sensor and that I presume is under the carpet. The car's year is April 2002 sp I imagine it will be a green sensor. Many thanks to everyone who responded
I'm going to bed bye bye!

Fred

[Fred Byrne]

Just to complete this episode. The SRS light went out by itself on Friday6 August. It hasn't lit since. I think I may have parked the car with the rear window slightly open and the carpet could have got wet. Then a few sunny days may have solved the problem. Needless to say, the new side impact sensor arrived on Saturday 7th August.
I had left the car slightly dismantled in anticipation of fitting said sensor. So have to put it back together. Thanks to all who responded.

Fred