2004 Rover 75 CLUB LE 4D Sedan V6 auto - Immobiliser
 

Hello,

Unfortunately my lovely black Rover 75 not longer starts, or more accurately has been starting intermittently before (eventually) not starting at all.

My local Land Rover dealer is stumped, saying that the Engine Control Computer is not communicating correctly with the immobiliser when I activate the remote key. He can't fix it. I've read the thread regarding the problem of battery low voltage affecting this issue, and also the need to have two keys. The battery is in tip top condition. Now this is the strange bit; I have two keys (originals), and both work perfectly to unlock the vehicle. But the immobiliser is (apparently) not activating to allow the engine to run.

Another strange thing, as I mentioned above, is that the problem began as an intermittent problem.

Now, the service people have a computer to assess my Rover, but this apparently, is not helping to resolve the issue.

This issue really has me stuck, since support for Rover 75's in Western Australia is now almost non existent. Worse, I'm not really that technically minded.

Lastly, the engine, when running, runs totally and absolutely perfectly after a recent top end service and head gasket replacement, plus change to a metal water thermostat. I've only done 92,000 Kms after 16 years so all should be good. The service people said my ignition coils and plugs are all good, and that the engine itself is absolutely fine. They are convinced it is an immobiliser issue.

I should also mention there are no fuel leaks evident, or problems with the fuel tank.

I'm hoping someone out there has some advice, or guidance, that I may provide the local Land Rover Service Centre in Perth WA. Thankyou again ...

Hello Lewis,

Does the starter motor turn but the engine doesn't fire?

Or is the starter motor silent?

Simon

The remote unlocking and engine immobilisation are separate issues. So if your car is locking and unlocking as it should on the buttons then the key fobs are working as they should.

The immobiliser part of the key is a separate chip in the key casing that is picked up by a coil fitted around the steering lock. You haven't modifed the keys to flip keys have you? That may cause intermittent starting problems as the chip may not get close enough to the coil each time.

Take the EWS unit out and have a look inside. Not unknown for water to get in there and corrode the circuit causing the sort of problems you are experiencing. Worth cleaning the plug contacts while you are in there.

Forum member genpk is in Perth too and has his own Toaf (diagnostic computer/system). I’ve used Toaf to check on the immobiliser ecu (EWS) - genpk can perhaps provide better information to help you and the garage.

Regards

Thankyou all and SD1too for getting back. Yes, the starter motor runs perfectly and the battery is is in excellent condition. There are no engine fault warnings either on the screen at the dashboard. Or any other warnings. The mechanic says that his test computer is flagging an immobiliser fault. Thankyou Mike Noc for the info. No, my keys are both originals and have been working perfectly up to now. But that is an interesting point. The batteries in the keys have been there for a long time and I've just realized/remembered that the range of both is quite poor. I'll get the batteries changed and see what happens. Thankyou vitesse, can you tell me how I would contact genpk? Is he perhaps in the WA Rover Club? Thankyou all.

To contact Perth member genpk find one of his posts like this one: https://www.the75andztclub.co.uk/for...d.php?t=236134 and click on his name on the left hand side. Usually gives you the option to either send a PM or email to poster.

Regards

I could be way off the mark here but as the problem was intermittent initially have you checked the solenoid on the starter motor? It's a classic symptom. Firstly check the small connector is secure and secondly the solenoid contacts within the solenoid?
Taking a power source direct from the battery to the small connector on the starter motor should cause the starter motor to activate, if it does not then the solenoid is the problem.
At least it is something you can look at, not over complicated and has zero cost to prove or disprove.

Thanks for confirming Lewis. Since the immobiliser ECU inhibits operation of the starter motor (and fuelling) it would appear to be working correctly in that respect. This must also mean that the transponder chip in your key and the immobiliser ECU are communicating properly with each other.

I'd say that the next stage is to check fuelling. Place your ear as close as possible to the fuel pump under the right hand side of the rear seat cushion and ask an assistant to turn on the ignition. Do you hear the pump running in a short burst of about two seconds?

If no, please report back.
If yes, with the starter motor turning can you hear the pump running continuously?

Simon

In a 2004 model, that sounds like classic Fuel Filter Syndrome (search term FFS).


TC

Thankyou again all,

I'll investigate your suggestions and get back. I'm suspecting that the techs here don't have much experience with Rover 75's. I'll try listening for the fuel pump and check the solenoid, although that does appear to be working at the moment because the starter does run OK. Hopefully I can eliminate the possibility of a complicated solution. By the way, shortly after I bought the car (new) the fuel tank stopped supplying fuel. The tech at the time said that a bracket had come adrift in the tank. I only remembered this on Saturday and mentioned it to the service people who said that it was not the same problem. I suppose it's not, but it struck me as that it could be that recurring. Anyway, I'll get back later this week. Thankyou again all for your thoughts..