1996 Range Rover Discovery multiple faults (ECU?)
 

Hello.

I am working on a 1996 Range Rover discovery that was given to us for use on a farm by a part owner of the farm. It has several faults, and before I go pulling everything apart I was wondering if these faults could all be related.

Faults;
The security system will not allow the starter to operate. The vehicle came to us with a button installed under the dash the to activate the starter.

The cruise control will not operate.

The tachometer signal is erratic.

The power windows with the exception of the drivers side window will not operate.

The Anti-Lock light is lit

Brakes do strange things, particularly on dirt.

Excessive fuel consumption, and I mean excessive! The other day I drove it in to town while my father flew to town in a light aircraft the same distance, and the Rover used twice the ammount of fuel!

It all seems like it's in some sort of "limp home" mode (perhaps EFI running in open loop?) and I was wondering if anyone else has had any similar experiences? Could it just be something as simple as a bad earth confusing the system?

Thanks,
Stuart

Let us "discover" what you have. A Range Rover and a Discovery are both vehicles made by Land Rover. What part of the world you are in is also of interest, as different models do exist.

The first thing I would like to troubleshoot with you is tachometer erratic. The tach is driven by a series of pulses from the alternator. When the alternator begins to fail, the tach will cease operation. This is driven by the small wire that plugs into the back of the alternator, not the large ones that bolt on.

There is a diagnostic connector, rated for OBDII, under the dash. You can buy a scanner to plug in, or most large parts stores will read it for free. We need to know the numbers of any codes stored. Certain codes keep the fuel system from going into closed loop fueling, making mpg bad.

You can download the RAVE, the factory set of shop, owner, and electrical manuals. Links below.

Sorry, it's a Land Rover Discovery. I always mix that up as it reminds me so much of a Range Rover. I am in Australia. I also forgot to mention that it is a petrol V8.

Thanks for the links, I will check them out.

Cheers,
Stuart

The Anti-Lock (ABS brakes) is supposed to shut off once you reach 10 mph, if it stays on all the time you have a fault, in the tech section on the DI page is a "how to" on finding out what is wrong.
Most people just pull the ABS PUMP fuse from the under hood fuse box, that will also stop your weird brake behavior on dirt roads.
There is no "limp" mode, they trucks not that smart.
Also in the DI tech section is a write up on fixing the alarm.
As for the excessive fuel usage, check air filter, tire pressure, tune up, O2 sensors.

Is it the 3.9 or the 4.0 It makes a big difference. The systems are completely different. I know both vehicles so starting with the engine works best. Plus the battery is dead causing the tac to act crazy.

1996 Landrover Discovery ABS Light Fault
 

In regard to the ABS fault. There are numerous threads on the site regarding this. Just too add to the many I have just fixed my 1996 Disco ABS Issue. Removed both front wheels and removed, cleaned and lubricated with gear oil both the left and right front ABS sensors and reseated. Instructions for removal are in both the Haynes and RAVE manuals. These sensors can gum up with grease and dirt causing them to lift slightly causing an airgap. Was a 1 hour job and appears to have fixed the problem. Unless you have seal kits do not remove the bracket that the ABS sensors fit into.

well, if you not sure about the fault code, a professional diagnostic tool would help you text and store the fault.

no need to pay a big fortune for the local garage unless the tool does complete no use fro ur vehicle.

In regard of excessive fuel consumption, check the fuel injector. My friend have a car with excessive fuel consumption in his shop, and later found out caused by clogged fuel injector. Also try to tune ecu, its an old car. I had him retune my second hand vogue when i got it, feel runs 10% faster and burns much less oil.