Citroen Zx Ecu

[harryh31]

Hello,

 

Does the Citroen ZX (P regn.) 1.9 cc diesel non turbo, 5door hatchback, advantage, have a

ECU.

 

The battery on my sons car exploded, and now, with a new battery we cannot start the car, it would appear that the keypad will not accept the code.

 

I have been informed from one scource that a power surge may have damaged the ECU. but another scource tells me there is no ECU on this model.

 

We have left the ignition switched for over one hour so that the ECU or whatever can reset itself, but to no avail, the engine turns over but will not fire, the battery is fully charged.

 

Any advice on this problem would be greatly appreciated.

 

harryh

[Guest Colin Hunter]

Hello Harry.

 

I am sure that your '96 1.9d ZX will NOT have an ECU for engine management. The fuelling on the 1.9d was controlled by a mechanical Lucas pump. Basically, the harder you press the accellerator, the more fuel is injected, whether or not the engine is capable of burning it! That's why you'll see older diesels smoking.

 

The immobiliser interfaces with a device on the pump which won't allow the fuel to go on without the relevant code. I have been told that if you try to remove this device you will wreck the pump, so be very carefull here.

 

It would appear that the voltage surge which happened when the battery exploded has damaged the keypad immobiliser and rendered it inoperative. If you can find one on a scrapper that has it's code with it then you should be able to put that in and restore your car to running order. Because you are able to change the code to anything you want, it is not likely that the pump is "coded". Once you put in the correct code the voltage is applied to the device on the pump and the engine will get fuel and run. Once the engine is running, it is possible to unplug the immobiliser and you'll never need it again! If you know someone who has a diesel ZX you may even be able to borrow theirs to get the job done. Unplug it with your engine running and give it back!

 

The immobiliser is just about the only bit of electronic whizzkiddery on the ZX! You could always try the factory default 1111 code in case the surge has "reset" the immobiliser.

 

Cheers Hope this helps. :rolleyes:

[harryh31]

Hello Colin,

 

Many thanks for your knowledgeable and prompt reply.

 

We shall be following your advice in trying to resolve this problem and will keep you informed on progress.

 

Kind regards and best wishes.

 

Harry.

[harryh31]

Hello Harry.

 

I am sure that your '96 1.9d ZX will NOT have an ECU for engine management. The fuelling on the 1.9d was controlled by a mechanical Lucas pump. Basically, the harder you press the accellerator, the more fuel is injected, whether or not the engine is capable of burning it! That's why you'll see older diesels smoking.

 

The immobiliser interfaces with a device on the pump which won't allow the fuel to go on without the relevant code. I have been told that if you try to remove this device you will wreck the pump, so be very carefull here.

 

It would appear that the voltage surge which happened when the battery exploded has damaged the keypad immobiliser and rendered it inoperative. If you can find one on a scrapper that has it's code with it then you should be able to put that in and restore your car to running order. Because you are able to change the code to anything you want, it is not likely that the pump is "coded". Once you put in the correct code the voltage is applied to the device on the pump and the engine will get fuel and run. Once the engine is running, it is possible to unplug the immobiliser and you'll never need it again! If you know someone who has a diesel ZX you may even be able to borrow theirs to get the job done. Unplug it with your engine running and give it back!

 

The immobiliser is just about the only bit of electronic whizzkiddery on the ZX! You could always try the factory default 1111 code in case the surge has "reset" the immobiliser.

 

Cheers Hope this helps. :lol:

[harryh31]

Colin

 

You are correct there is no ecu on the zx

 

However there is a small 1" square box with a rubber cap covering a reset push button, in the wiring circuit from the pump, under the bonnet............apparently this little box contains a magnetic switching device which will become disconnected if the vehicle is towed, as was the case here, after the battery exploded. thus preventing the code pad from working

 

It was a faulty voltage regulater on the alternater which was charging the battery at to high a voltage which caused the battery to explode.

 

After the new battery and a new voltage regulater had been fitted........the car would'nt start until the reset button had been pushed on the little box previously referred to .......all is now well.

 

Harry

[Guest Colin Hunter]

Hello Harry.

 

Glad to know you've sorted it out without recourse to changing the keypad. I'd actually forgotten about the reset button. Both my XUD Xantias had them so I should have twigged, only I never had any problems in that area so no need. Are you going to continue using the keypad, or disconnect it once the engine is running? Many people do this due to the constant need to enter the numbers. Most of them up here are still 1111 as they never bothered to change them!

 

Cheers. Happy motoring! :lol:

[harryh31]

Hello Harry.

 

Glad to know you've sorted it out without recourse to changing the keypad. I'd actually forgotten about the reset button. Both my XUD Xantias had them so I should have twigged, only I never had any problems in that area so no need. Are you going to continue using the keypad, or disconnect it once the engine is running? Many people do this due to the constant need to enter the numbers. Most of them up here are still 1111 as they never bothered to change them!

 

Cheers. Happy motoring! :D

[harryh31]

Hi Colin,

 

My son will still use the keypad with his own code, its another security measure........cars are stolen with alarming regularity in the west midlands.

 

I've been looking at some pan photos of Brae, it looks a beautiful area, very remote, and "fresh" unlike where I live .....wall to wall houses in each direction for 10 / 20 miles. We have the motorway M6 Junction 9 about a mile away, its handy for getting away to distant places, that's when you can risk not getting stuck in the traffic, which is horrendous........thats why your closing remark " Happy motoring" bought a smile to my lips.

 

Those where the days !!!!!!!!!!

 

Harry