Scenic RX4 - won't start & loss of clutch pedal

[Markie76]

Hi,

My cousin has a 2005 2.0 diesel Renault Scenic RX4 which is not running due to;

1. Immobiliser not turning off.

A few weeks ago when he returned to the car it refused to start(turned over ok). A few 'mehanics' have looked at it and have stated the immobiliser isn't switching off and enabling the fuel circuit. He has removed the ECU/immobiliser and had it looked at - the initial feedback was that they can deactivate the imobiliser (enable the fuel permenantly) at a cost of £160+vat - but as its a diesel there are no guarantees that it will work. They state if it was a petrol then their method works flawlessly.

2. Loss of clutch pedal.

When driving at motorway speeds after a period of time he looses the clutch pedal and cannot change gear. He says the pedal goes soft and does nothing when depressed. When the car is parked up for a couple of hours the clutch pedal works as normal.


Can anyone offer any advice? He can't afford to part with £800 for Renault to fit & program a new ECU/immobiliser unit.

From internet searches I understand the Megane immobiliser has a history of playing up?
Does this also apply to an RX4?
Is is it true a diesel Scenic RX4 immobiliser is more complex than the petrol version?

Don't know if its worth mentioning that when he bought the car it only came with one key. He went to Renault to get a spare and they sold him one and programmed it for £200. However, this spare key has never been used to date.

Thanks in advance,

Mark

[lagunav6]

Hi Mark,

I will try and help you but could do with some more information. From my experience ecu's very rarely fail, and are often condemned without any real justification. What I would need to know is when you crank the vehicle over what is the state of the imobiliser light in the centre of the dash? (Red LED that flashes when the ignition is off) If it flashes very quickly then that would indicate an imobilser fault - possibly the key, the decoder ring (that reads the key and is located around the steering lock) or the decoder unit itself.

If it doesn't light up at all then that would indicate a lack of power to the ecu or the decoder unit, but as mentioned earlier not necessarily the ecu itself. If it stays permanantley glowing then that would indicate that the key is being read but something else is preventing it from starting. By far and away the most common cause of this type of fault is the crappy wafer thin wiring used by Renault in their vehicles. Often the problem is a corroded terminal or broken wire in a loom causing such a fault. The only method then is painstaking wiring checks with a multimeter but of course with out the diagnostic equipment plugged in first to give you an idea this will be like looking for a needle in a haystack.

One other suggestion would be to try the new and unused spare key and see if this has any effect. If it starts then obviously the key is at fault, if not watch the LED and see if it performs any differentley. On these models the battery in the key has no effect on the starting of the vehicle and is purely to operate the central locking.

Let me know what happens and I will try to guide you further.

Regards,

LagunaV6.

[Markie76]

Hi LagunaV6,

Thank you for your reply.

I have told my cousin, he needs to get his immobiliser box back and reinstall it, then we will carry out the tests as suggested and get back to you. Might not be until after the weekend.

Thanks,

Mark.

[Markie76]

UPDATE:

My cousin has been working and I haven't had a chance to see him and carry out the immobiliser tests as suggested.

However, he called me last night and told me he had refitted the immobiliser/ecu box and got the RAC to tow him to a local independant garage which had done computer diags for him before.

They initially told him some component on the fuel circuit or pump/injectors had gone and it would cost £300 + VAT to replace and have the car running again. I think he agreed to this.

The next day they phoned him back and said they had fitted the new component but the car wasn't running and now they suspect a timing belt problem. He's not engine savvy but from his explanation they are suggesting the timing belt is either the wrong one or fitted incorrectly - misaligned and their justification so far seems to be based on not finding a part number on the belt. They now say they suspect bent valves and damaged pistons and will need to dismantle the engine, inspect and replace them at a cost of £1500. I know the timing belt was replaced within the last 12 months and if it is an aftermarket part where the markings have come off this is irrelevant as the car worked fine for months after and its not that the belt has now snapped. If it had been fitted a couple of teeth out then he would have known as you would expect tell-tale signs.

I think they are taking him for a ride. He can't afford to spend (it makes no sense) £1.5k on a car that was worth £3k.

Do you know if the RX4 2.0 diesel is a non-contact engine?

I have advised him to tell the garage that as they have failed to get the car running with their initial £300 fix, they should remove the new component, return the car and he will pay the diagnostics fee, nothing more.

Is this reasonable?

I must appologise on my cousins behalf as I wasn't expecting him to just go ahead and do this.

Thanks,

Mark.

[Hensem40]

Originally Posted by Markie76

UPDATE:

....However, he called me last night and told me he had refitted the immobiliser/ecu box and got the RAC to tow him to a local independant garage which had done computer diags for him before.

They initially told him some component on the fuel circuit or pump/injectors had gone and it would cost £300 + VAT to replace and have the car running again. I think he agreed to this.

The next day they phoned him back and said they had fitted the new component but the car wasn't running and now they suspect a timing belt problem. ...

Mark.

I dont own a RX4 diesel but I am very very sure that the car has been running on that timing belt for quite some time. without any problem. It is not like he suddenly on a highway has and engine failure....

So personally I think the mechanics no nothing about the RX4.

What I am interested to know is how did u solve the clutch problem? I have the same problem when ever I go long distance and lately I have clutch pump problem. Mechanics are telling me i need a new master pump and a new slave pump for the clutch. Added to this they told me the slave pump is inside the gearbox and I have to have it opened to have it repaired? what shall I do?

Does anyone have any repair manual or diagrams for this particular part of the engine?

[Markie76]

Hi,

As far as I know the car is up and running again but the clutch problem hasn't been looked at.

I did hear/read somewhere that loss of clutch is a design flaw in that the hydraulic line runs too close to an exhaust pipe and therefore heats up to the point where nothing happens when you depress the clutch pedal. Obvious symptoms would be that from cold everything works ok, then once some engine heat has been generated you lose the clutch, after standing and letting it cool down everything is back to normal.

Might be worth exploring before you hand over cash to the mechanics.