I have a 2006 TD6, Icarsoft CR Pro shows up a Link Error when trying to connect to SRS and and Land Rover SDD does not recognise the Restraints Control Module. Any advice on where to start looking would be appreciated

First thing with no comms is check +ve & -ve connections, then data lines (CAN-H)


**DO NOT** have the module unbolted for diagnostic purposes and connected to the harness, if the vehicle detects a rollover (i.e. the module moving upside down) it will trigger the airbags.

** DO NOT** work on the SRS system without understanding the potential hazards involved and only measure voltage, never resistance unless you are confident both ends of the circuit are disconnected from all SRS devices, also only use the correct wiring diagrams for your vehicle, generic ones may be incorrect.

Thanks for your prompt reply Phoenix, can you be more specific please, which +ve and-ve connections do I check and how do I check data lines (CAN-H)

Here's the wiring diagram, there is no CAN-H, that's later vehicles, it's K-BUS which is single wire (pin 9), expect to see 7-12V on that, the +ve is on pin 5, the module appears to be grounded through it's mounting so unless it's corroded around it's fixings, that should be OK.
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If you can, de-pin the K-BUS from the connector, check the wire for voltage, then check the module by probing the connector housing, if you get nothing from the module on that pin - with the ignition on, then the RCM has an internal defect, if you do, but nothing on the wire, then it's a wiring issue.

If you can't de-pin the housing, then it's acceptable to snip the wire for testing and join with a heatshrink crimp connector after testing is completed.

Thanks for the prompt reply and information, I'll try that

Hi there,

What are you plugging into the OBD socket? On my icarsoft for my 2006 4.2SC in order to test the SRS module i had to tell it that the car was a 2002-2005 model and not 2006. In 2006 LR still used the old BMW SRS module. If i scan mine on the 2006 model setting then it tells me there is a link error. Worth a try?

Paul

Thanks for the reply, that is interesting I will try that before removing the centre console to test the module

If you've also tried SDD, then it's unlikely to be a protocol error.

Thanks for the reply

Phoenix, that really helped me a lot, thank you - my SRS ECU is knackered I am pretty sure

I bought a second hand ROVER VOGUE L322 BMW SRS ECU Airbag YWC000710 for my 2004 car, is it OK just to change over the ECU's - they don't need programming or anything like that do they ??

SRS modules are VIN-tied when coded during fitting, the coding (i.e. what is fitted to the vehicle) should be the same if it's from an equivalent model year.
I'm afraid I can't say if the incorrect VIN will be an issue as I've never dabbled in fitting used control modules - TBH, all you can do is try it *BUT- VERY IMPORTANT* make sure the module is bolted down to the vehicle before connecting it. I've seen the airbags go off in a car because the tech didn't bolt the module down before powering it up, then turned it on it's side to get it in it's mounting position - the sensors in the module triggered a 'rollover' response....

Best case:- DTC stored in IPK etc. for incorrect VIN in the SRS module, everything else functions as expected (i.e. no DTC's for missing inputs or open-circuit outputs etc.)

Worst case:- SRS light on dash, lots of DTC's everywhere.

Phoenix - thanks for the heads up, we carefully swapped out the SRS ECU and took note of your advice, and it seems to have worked for now, fingers crossed

A top tip if anyone else has to replace the SRS ECU - take the centre console screws out and lift the rear of the console up and slide a broom straight across the seats to hold it up out of the way.

The ecu is under the heater blower fixed to a metal frame, unbolt from frame to remove the ecu ( aka DCU )

Click image to enlarge

Good result! - the other thing is I suppose you never know if the replacement module is any better until you power it up. Are there any DTC's due to the VIN change?

Out of morbid curiosity, what was the defect in your previous module?

no faults on Snap-On scanner, and no fault codes on my IID scanner

the old SRS ecu/dcu looks OK, but I have not opened it up, and to be honest can't be bothered - we will see what the next 500 miles brings - and if the ECU swap has done the trick

Sorry, I meant what was the reason for changing it?