Airbag fault 22 any thoughts on where to start?

[brozier]

Hiya,

I have a 2001 2.2i with the MRS3 Airbag module fitted. It has driver, passenger and side air bags.

I'm trying to get it MOT'd after lying idle for a year. Its been on axle stands whilst we replaced a brake line.

It had an airbag light on and INPA says 2 errors :-

22 MRSA front left
Error frequency: 1
Error not active at the moment
Communication Error
error is not sporadic.

22 MRSA front left
Error frequency: 2
Plausibility Error
Error not active at the moment
error is sporadic.

I've reset them for now so hopefully that will get me through the MOT.

Any ideas where to start looking?

Thanks

 

[t-tony]

If the codes clear and don’t reappear you really don’t need to look at all.

Tony.

ps. Having said that I would be making sure the carpet underlay is dry and not holding many litres of water.

 

[brozier]

If the codes clear and don’t reappear you really don’t need to look at all.
Tony.
ps. Having said that I would be making sure the carpet underlay is dry and not holding many litres of water.

Thanks Tony,

The car lives outside and carpet is slightly damp to the touch under the seats I'll have a look underneath if the codes come back.

Seats out job I assume?

Cheers

 

[mrscalex]

The code is for the left side imact sensor which as Tony suggests lives under the carpet. And it can indeed become faulty if that area gets wet.

If it's a genuine one off and doesn't come back ever again fine. But if it comes back again later it's an intermittent fault (not unsual) so remember it could let you down when you need it.

It's not a big job getting the seats out and most Z3s will have some damp that needs attending too. Without removing the interior completely the best course of action is to pull carpets up as best as you can/wring out/mop up what you can then put a dehumidifier in there. But remember the water will come back again unless you locate the source. Frequently it's the seals at the top of the windscreen A-pillar but could be other sources including the hood seal on the rear bulkhead.

Worth noting if the top of the carpet is damp then either it's coming from the A-pillar and sitting on top of the carpet or balance of probability as your sensor appears to have got damp it could be very wet when lifted.

 

[NZ00Z3]

As suggested by others, definitely check for dampness under the carpet on both sides. The left side has an airbag impact sensor and a yaw sensor. The right side has an airbag impact sensor.

 

[t-tony]

Thank you Rob and Murray.

Tony.

 

[brozier]

The code is for the left side imact sensor which as Tony suggests lives under the carpet. And it can indeed become faulty if that area gets wet.

If it's a genuine one off and doesn't come back ever again fine. But if it comes back again later it's an intermittent fault (not unsual) so remember it could let you down when you need it.

So the light did come back, seat is out and area quite damp I will dry it out today and see if the sensor is still working okay. Has a little surface corrosion but not much, I wonder if water got into the connector.

Does the sensor need a decent earth connection through its case I wonder?

Thanks

 

[brozier]

A quick update. The wiring and connector to the Temic sensor didn't seem wet or corroded. It was just the aluminium part of the sensor and it mounting screws. I spent quite a bit of time removing this corrosion and cleaning up the clips where it mounts to the body. A liberal smear of vaseline over these areas should keep the damp out.

The connector only has two wires going to it despite it being a three pin connector. This makes me think the earth is through the mounting screws?

I've dried out the area - I think the rubber cap on the top of the B pillar was loose so maybe the cuplrit.

Now getting no faults at all. So think it is fixed. It's only driven to the MOT garage so far so not an conclusive test but I'm hopeful...

Thanks again

 

[mrscalex]

Get yourself some black Stormsure and put a decent pool of that over the bung.