I'm trying to help someone get there vehicle rolling again. He was in a parking lot and started the 2003 Discovery II and started to drive away when it just stalled. He attempted to start it, it would start for about two seconds and die.
He had it towed to a mechanic shop and they checked everything but all they could find was a "Alarm data serial link fault". They replaced the CPS and no change in behavior. The security light goes out when unlocking the vehicle. When locking the vehicle it flashes fast and then slows down in a few seconds. The alarm hasn't sounded when opening the doors. I asked about the fuel pump and was told it was replaced a short time ago, about a month ago.

How does the alarm work on these vehicles? Any info I can read about this alarm system?


We need some new ideas on the solution to this problem. Thanks

 

If it starts it isn't the alarm.

The only problems I have had that allow the vehicle to start are fuel pump, battery, catalytic converter, mass air flow sensor, and vacuum leak. But it ran poorly and stalled with each of those. Do you have a code reader that shows current and pending codes? That might help.

 

What's the exact code?

 

The shop used a Maxidas DS708 and the fault code was 4.

 

That doesn't really tell us much, unfortunately. We need the industry standard codes that start with P (for powertrain) usually. Something like P1668 or p1884.

If they clear the codes and you restart the engine does that code come back? Sometimes the codes are just historical communication error from a battery being replaced or something, and they might not mean anything is wrong.

 

There isn't any codes other than that #4.

The shop has checked all the fuses and they are all good.

Would a Nanocom be of any help in fixing this problem?

 

Depends what the problem is. Code 4 means nothing to me, unfortunately. Do they have a cheaper code reader they can put on it that gives normal codes?

Did they check fuel pressure at the rail? It's hard to see, but if you feel for it, there is a ford style test port under the upper manifold near the firewall.

 

Agree those codes just don't help. Standard OBD-II codes are what is needed. A cheap code reader should give those codes.

Sadly, the codes don't tell the whole story. Sometimes a certain combination of codes will point to a particular problem that you would not be able to guess from the individual codes. For instance, misfires and poor performance (both of which will generally generate codes relating to, well, misfires, and maybe lean conditions) can indicate a faulty mass air flow sensor (which is easily replaced) even though there is no MAF code.

If your friend gets a cheap code reader you should be able to simply Google "land Rover p0xxx" where xxx is the numeric code, along with the other codes, and chances are someone has had the same set before. Certainly, if you post them here you will get good advice (I have gotten great advice on codes here, numerous times, and saved literally thousands of dollars).

Best of luck.