SRS fault light on permanently

Yesterday the SRS fault light on my L322 TD6 came on and is now on all the time. No errors are displayed in the message centre.
have had a search for old posts and can find plenty for P38's suggesting problems with the rotary connect on the steering wheel and loose connections under the seat, but nothing definitive for a L322.
No work has been carried out on the car for months (unless you count sticking a litre of oil in last weekend), so a bit mystified.
Any suggestions before I resort to a trip to my local LR dealer?

SRS is a "HARD" fault it can only be removed via "Testbook" so you'll HAVE to go to LR Dealership to remove it anyway ..

Made a note in my diary. Simply said... 'bugger!'

the hooded claw said:

SRS is a "HARD" fault it can only be removed via "Testbook" so you'll HAVE to go to LR Dealership to remove it anyway ..

Click to expand...

Wrong, there are hard and soft faults on the SRS, a bad connection under the seat for the side airbags will give an SRS fault that will clear with the next ignition cycle on the P38. There are 2 bulbs for the SRS Light, if one fails it will also give a soft SRS fault that will go on the next ignition cycle after the bulb is replaced.
On the other hand, a fired airbag fault cannot be re-set with Testbook, Faultmate etc.

I got this problem too.

Even Land Rover stealer can't help me - said it was a voltage issue (something about 9.6v somewhere in the system) but that's as far as they could see.

Could be either faulty ECU, bad connection or something wrong ith one of the many air bags roaming the cabin.

It bugs me that my car has only done 36,000 miles and has cost me thousands in just plugging the bloody thing onto the dealers stoopid computer.

Looking forward rsw's new system where I can fault find and reset these things myself.

Last major problem was "Trans Failsafe Mode" - Stealer diagnosed broken transfer box, quoted me £1300 to fix when it turned out to be a faulty switch which needed a little lube, costing naff all.

Sorry to have gone off on one but SRS problems are seriously difficult to diagnose.

the hooded claw said:

SRS is a "HARD" fault it can only be removed via "Testbook" so you'll HAVE to go to LR Dealership to remove it anyway ..

Click to expand...

Dealer told me that after 5 cycles with no faults the system will reset itself.

I don't believe it for a second though.

Apparently, they reset mine and the light came back on straight away. Another waste of £80

I love my car though - wouldn't drive anything else

milonic said:

Dealer told me that after 5 cycles with no faults the system will reset itself.

I don't believe it for a second though.

Apparently, they reset mine and the light came back on straight away. Another waste of £80

I love my car though - wouldn't drive anything else

Click to expand...

No point in the reset if you have not fixed the fault. One of the great advantages of owning a faultmate is that you can check the wiring and turn off the fault as many times as you like until you get to the fault.

might be worth investing in one then?
Might book it into LR just for a looksee and see what (if anything) the come up with.
Thanks for your input guys

is that a hard fault ??

Just had the thing plugged in (nice LR Specialist in Maidenhead did it FOC), and came up with loads of errors. According to the guy, the first two probably relate to the actual problem 'SUPPLY VOLTAGE' & 'INTERNAL ERROR', the rest are all faults on the individual items in the SRS system, and would probably go away if one of the first faults were rectified. He cleared the faults a couple of times, but they came straight back.
He said he would check the voltage (as per a previous post) and if that was ok, then he'd be looking at replacing the SRS ECU itself.
Question 1 - where is the SRS ECU, and how do i get at it
Question 2 - What should I be testing to determine low voltage, as I assume the thing will be connected by a big multi plug with one pin supplying the current?

Any other tips anyone could supply would be gratefully received. If all else fails I'll take it back to them and get them to sort it out, but might as well have a go myself first.

bigdel said:

Just had the thing plugged in (nice LR Specialist in Maidenhead did it FOC), and came up with loads of errors. According to the guy, the first two probably relate to the actual problem 'SUPPLY VOLTAGE' & 'INTERNAL ERROR', the rest are all faults on the individual items in the SRS system, and would probably go away if one of the first faults were rectified. He cleared the faults a couple of times, but they came straight back.
He said he would check the voltage (as per a previous post) and if that was ok, then he'd be looking at replacing the SRS ECU itself.
Question 1 - where is the SRS ECU, and how do i get at it
Question 2 - What should I be testing to determine low voltage, as I assume the thing will be connected by a big multi plug with one pin supplying the current?

Any other tips anyone could supply would be gratefully received. If all else fails I'll take it back to them and get them to sort it out, but might as well have a go myself first.

Click to expand...

If you are talking about a P38, the SRS ECU is under the centre console panels. Look at rangerovers.net for info on how to remove the side panels. It is connected via a multiplug. Be very careful, make sure you disconnect the battery at least 15 minutes before you start, and have your EKA code ready in case you need it.
There is no connection as far as I can see between the SRS ECU and the BECM. The SRS ECU has it's own comms pin in the OBD socket and it communicates direct with the instrument cluster to display the airbag fault message.

The DCU (Diagnostic Control Unit)

The DCU is installed on the top of the transmission tunnel, alongside the handbrake, and controls the operation of the
SRS. The main functions of the DCU include:
l Crash detection and recording
l Airbag and pretensioner firing
l Self test and system monitoring, with status indication via the warning lamp and non-volatile storage of fault
information.
Accelerometers in the DCU provide crash detection for front and rear impacts. A safing sensor provides confirmation
of a frontal impact. Various firing strategies are employed by the DCU to ensure the airbags/pretensioners that are
fired are appropriate to the severity and direction of the impact. The firing strategy used also depends on the inputs
from the seat belt buckle switches and the occupancy detector sensor, and varies between NAS and other markets.
An energy reserve in the DCU ensures the firing signals can be produced for a minimum of 150 milliseconds after a
crash is detected, in case of disruption to the system power supply from the ignition switch.
When the ignition is switched on the DCU performs a self test and then performs cyclical monitoring of the system. If
a fault is detected the DCU stores a related fault code in memory and illuminates the SRS warning lamp. Faults can
be retrieved by TestBook/T4 from the DCU via the K bus connection with the instrument pack. If a fault that could
cause a false fire signal is detected, the DCU actively disables the respective firing circuit, and keeps it disabled during
a crash event.



Pin No. Description Input/Output
1 RH front seat belt pretensioner positive Output
2 RH front seat belt pretensioner negative Input
3 LH front seat belt pretensioner negative Input
4 LH front seat belt pretensioner positive Output
5 Auxiliary power Input
7 SRS warning lamp Output
8 Front passenger seat belt buckle switch (where fitted) Input
9 K bus Input/Output
10 Driver airbag squib 1 positive Output
11 Driver airbag squib 1 negative Input
12 Driver seat belt buckle switch Input
13 Passenger airbag squib 1 negative Input
14 Passenger airbag squib 1 positive Output
15 Seat occupancy detection Input
16 LH side airbag negative Input
17 LH side airbag positive Output
18 RH side airbag positive Output
19 RH side airbag positive Input
20 LH side impact sensor Input
21 RH side impact sensor Input
22 to 25 Not used –
26 Driver airbag squib 2 negative Input
27 Driver airbag squib 2 positive Output
28 LH rear head airbag negative Input
29 LH rear head airbag positive Output
30 to 32 Not used –
33 Passenger airbag squib 2 positive Output
34 Crash signal Output
35 to 39 Not used –
40 Passenger airbag squib 2 negative Input
41 RH rear head airbag negative Input
42 RH rear head airbag positive Output
43 and 44 Not used –
45 LH front head airbag negative Input
46 LH front head airbag positive Output
47 RH front head airbag positive Output
48 LH front head airbag positive Input
49 Battery disconnect unit negative Input
50 Battery disconnect unit positive Output
51 to 75 Not used –

Flippin 'eck, I knew it was gonna have a multi plug going to it, but didn't realise it would be quite that big! I don't think I'll bother with the DIY, I think just I'll pay someone to have a look at it.

By the way, it's a 2003 L322 TD6.

bigdel said:

By the way, it's a 2003 L322 TD6.

Click to expand...

Yes the above is for the L322

Would really take the time to check the state of your battery and alternator, I had the SRS fault on my P38 on and off for weeks, I checked the cables and it would come and go. The battery eventually packed up as did the alternator with both replaced the SRS fault has gone...

Had a new battery about 6 or 7 months ago.

How does the centre console come apart so I can at least have a look at the ecu itself?

Took the car back to the Specialist today and they (in consultation with land Rover technical support) have diagnosed that the SRS ECU is f:censored:d!
They have tested all the connections but every time they try and reset the faults they just re-appear.
They asked if it had been in a collision as that might account for this type of fault, but the car's not been in any accidents. Well, none that I've noticed anyhow!
Upshot is, it's gonna cost £600 to supply and fit the new ECU
Oh well, at least i got a free valet

New ECU fitted, little light on the dash now gone out. All's well with the world

bigdel said:

Upshot is, it's gonna cost £600 to supply and fit the new ECU

Click to expand...

Doncha love the way they can look you in the face, say 600 quid and never crack a smile .....