Hi All,

I need some guidance please. My SRS light comes back on after start up. No Flashes.

My Mechanic has been unable to get any SRS error codes. He assures me he has all the right Scanners.

He has checked Clockspring and all the wiring and thinks it could be the SRS module.
He has given up and returned the car to me!

I need to get this sorted as it will not pass its Warrant of Fitness test!

Any help would be greatly appreciated.

 

JTIS DTC list of possible causes for no DTC, but SRS light staying on constantly is as follows:

Instrument pack to diagnostic module AIRBAG SRS with ignition ON MIL circuit: open circuit or high resistance (See * below)
Ignition switched voltage to diagnostic module: open circuit, high resistance or short circuit to ground (See **)
Diagnostic module failure (Integral to SRS Module)

* That's the Yellow/White wire from the SRS module (RH A post, Black 12 way connector) and the SRS diagnostic socket (Also RH A post) to the instrument panel (24 way black connector)

** Which is strange because the electrical diagrams show only a permanent 12v battery supply to the SRS diagnostic socket on a Red/White wire

 

Hi,
Thanks for your help. The Airbag light does go out but returns shortly after Startup.
I have the panels off so will check wiring you mentioned.
Also read that the module has its own back up power.
Maybe a faulty battery. Car is 20 years old. Has been well looked after and only
36000KM. Its actually a 1996 model so a very early one.

Thanks Greg.

 

If you find no fix for this then I would think about looking at the main car computer. 97 models are well known for having all kinds of issues for some owners with the main computer (it got me when I had a 97) causing the cars to present problems that are not really there. It is a long shot but if you don't find a fix it may be worth sending out for a bench test and possible repair as eventually if you own the car long enough it will fail and cause other issues.

 

I've never heard of, or seen in the electrical diagrams, any battery back-up for the SRS, although there is a capacitor based, deployment power energy reserve built into the SRS module. That's why, when working on the SRS system, Jaguar recommend disconnecting the car's battery and waiting at least one minute for it to discharge before starting work.

Later Edit! Just found the JTIS reference about the main ECU having a back up battery to ensure airbag deployment in the event of loss of main battery power in a crash. I don't know how the SRS system is safeguarded from being operated by that battery while working on the system with the main battery disconnected!

 

Hi,
Just read description in service manual for SRS Control module.

States- The Control Module includes an internal battery backup power supply enabling Airbag deployment in a crash situation if battery cable dicconnected.

 

Have finally resolved problem, ordered a 2nd hand Air bag module from Amazon.
Terrible thing to get to, it is up on the right hand side drivers A Post. Had to remove drivers seat so I could stretch out!
Wasn't confident this would resolve issue so very relieved.
Also have just replaced all front and rear shocks as well as mounts.
Replaced upper tensioners. originals in as new condition.

So hopefully can start enjoy driving it!