QuestionQUESTION: Hi, I have a 1996 Discovery SD. I left it sitting for about 2 months and the battery went low. I have since replaced the battery with a new one, but the car has a problem where it will not crank. It does start occasionally, but most of the time it doesn't. I have tested the starter and it seems to be working. I tested the connection from the ignition to the starter and it is not getting power. I thought it might have something to do with the alarm system, so I removed the 2 fuses to the alarm; when I do that, the engine will crank but not turn over (I assume because the theft deterrent prevents it.) Does this mean the starter and ignition switch are okay? Could there be a problem with the alarm system or immobilizer? Does this model have the spider alarm? It was made March 3, 1996. Any suggestions would be greatly appreciated. Thank you in advance.
ANSWER: I'm sorry to say none of your questions are answerable with the data you present. All I can offer is some general information which may help . . .
First, all US market Discovery models use a combined central locking/pushbutton entry/alarm system that cannot be removed from the vehicle because the engine ECU won't allow the engine to run without an OK signal from the alarm. Additionally, the locking and entry functions are irremovably tied to the alarm in the same box. If you unplug the alarm or pull those fuses you run the risk that the alarm and engine controller will fall out of sync, in which case the vehicle will not run until the sync gets restored via the Land Rover diagnostic system. In most cases that means a tow to the dealer or LR specialist.
Next . . . when talking about car problems it's important to have the terminology clear. Cranking refers to the starter rotating the engine. If the car cranks, that means the starter motor turns it over. Starting means the other systems work, and the engine starts and begins to run when it is cranked. Your post sort of confuses those two states.
Most people equate turning over with cranking, though some equate it with starting. Since that's a bit ambiguous I'd avoid that phrase.
To solve your problem you first have to answer this: Does the car have a problem cranking, or does it always crank but have a problem starting?
If the former, you need to diagnose the cranking circuit. If the latter, you need to diagnose the running circuits . . . fuel and ignition.
You can start by going online and buying a workshop manual and electrical troubleshooting guide, or you can buy a day's access from the official Land Rover site for $20/day and download it all there. The site is www.landrovertechinfo.com The benefit of the factory site is that it's the real deal, and it has a lot of training material you can download too.
Best of luck with this
Check my car blog at http://robisonservice.blogspot.com
John Elder Robison
---------- FOLLOW-UP ----------
QUESTION: Thank you for your quick response. I have since taken apart the dash and discovered the truck is not fitted with a Spider unit nor a bypass, so I assume it has another type of alarm system.
I have also narrowed the problem down to the rear door sensor (the small button that turns on the interior light). Whenever the rear door is shut (and the button is pressed in) nothing happens except for a clicking beneath the dash. With the rear door open and the button unpressed, the truck starts right up. I switched the button with one from another door and it made no difference. So I assume the issue is not with the button itself, but with the wires that connect to it.
The sensor button works in that it turns the interior light on and off, but it seems to be immobilising the truck. Are the door sensors connected to the alarm? Is there a way to fix this? Again, thank you for any insight you can provide.
AnswerIf the car's starting behavior is affected by the locking of one door, you have etablished that it does have the standard security system. Presumably there is a problem with that lock actuator and it's keeping your vehicle from starting. You may want to go to Land Rover's official site, www.landrovertechinfo.com and buy a day's access to download the relevant wiring diagrams and service instructions.
Good luck with it
Check out my car blog at robisonservice.blogspot.com and find me on facebook/robisonservice
John Robison
