Good day,

I wonder if anyone can offer some words of wisdom. As you will probably gather from reading this thread I am not a mechanic or an electrician! My '98 XK8 has developed some sort of airbag/SRS fault.

I get the one flash followed by two flashes cycle before the airbag light is permanently displayed on the dashboard. I have done a little bit of reading around it (but a little knowledge is dangerous, especially in my hands!) I've checked the connections under both front seats and had the ignition cowling off to examine the connectors to the stalks etc all look ok. I then went around checking any Airbag related fuses around the vehicle and found that fuse 4 (10 A) on the driver's side, RHS (UK) cabin fuse box had blown. Upon replacing it, found that it blew again when I switched the ignition back on. I replaced this with a 15 amp fuse (this blew too) as did a 20 amp fuse. In between all this I had disconnected the battery to see if any sort of a hard reset would help. I have tried a 30 amp fuse, this didn't blow but didn't get rid of the error either.

Has anyone had a simple problem? I'm thinking that it may be the clock spring that is faulty, as intermittently the indicators don't sound which potentially indicates something isn't right. Also the fobs haven't worked since I have had the vehicle so I have to use the key to enter. Again intermittently you get the warning sound when you open the door, but more than often now I don't. Is that potentially part of the same problem?

Anyway, I'll throw this out to the experts any advice gratefully received.

Best wishes

Mark

 

I forgot to add, before inspecting the fuses I tried using an OBD reader which didn't bring back a fault code. I also went to a garage with a far more sophisticated system, again no fault code came back to assist in diagnosing the fault.

Cheers

Mark

 

As for the fobs..dismantle so you can see the circuit board ..clean with thinners ( not WD 40 ) where the contact rubbers press and re new the batteries. Check the aerial connection just to the rear of the battery .
As for the SRS I fixed mine permanently by removing the dash clocks and fitting a timer to shut off the light after 5 seconds. That way you get your MOT and can conduct further tests for the fault.
Here is where you will find all the codes .yours is on page 15 not 16 and sounds like its under the seat.

XJ501-09 (jagrepair.com)

 

Thanks so much for your reply, I really appreciate your input.

The mind boggles, could you possibly elaborate about fitting a timer to the airbag light (part number, where to buy, how to fit) for me please as I haven't a clue. The 1-2 code seems to indicate a problem with the restraint control module according to the list you kindly posted but will go back to the seats and double check the connections as well.

As for the key fob, I had already disassembled it and cleaned it thoroughly with iso-propanol following an on line tutorial. Changed the batteries in it too. It didn't work and the car wouldn't go into programming mode either, will have the aerial checked too, thanks for that tip otherwise I'm going to send the SLM off to be looked at by a specialist.

Best wishes

Mark

 

To fit the timer you need to remove the clocks ( easy) remove rear cover ( easy) cut a track on the circuit board and solder two wires that go to the timer ...are you up for that ?
You an also pass a uk MOT if the warning light does not work which is slightly easier .

Which do you want?

See here
Common mistakes made by MOT testers - Matters of Testing (blog.gov.uk)

 

Many thanks, I think I'll certainly be able to remove the gauges, whether my soldering skills are up for the next part I'm not sure but prepared to give it a go in a week or so when I may have a bit more time. I'm assuming the timer itself is easy enough to source?

Best wishes

Mark

 

Will right it up for you ..
The timer is here
DC 12V Delay Relay Shield NE555 Timer Switch Module, Adjustable 0 - 10 Second | eBay

Various sources mine cost £1.20p !!
12v ignition switched and two wires into the 3 positon connector.
a 1m length of some thin twin wire like the stuff inside burglar alarm wiring and a small fine soldering iron.
Wire for + and - cables

 

I will write this up as a separate post " Testing the SRS system and defeat the SRS light"

 

Just a quick update, had the XK8 put on better diagnostics today. Although the Airbag fault has been cancelled and the light isn't coming on, it is in reality probably only a temporary fix. The voltage going from the control module to the restraint module is low (10.5v rather than 14v.) The battery and alternator are well within spec, so it is likely to either be degraded wiring or connections. Will need to get this seen to in due course. Hopefully it will be a fairly easy fix.

Best wishes

Mark