Going through our '01 Disco maintenance, etc. and I just had three codes pop up on me today. They are...

P0563 - Battery voltage not plausible Drive cycle A:Signal out of range - above maximum.

P0447 - Purge canister vent valve/DMTL power stage fault Drive cycle C:Signal missing.

P1668 - Anti-Theft Alarm serial link fault Drive cycle A:Signal out of range - above maximum

I included what their descriptions are but honestly I don't know what they really mean. Maybe some of the more experienced can help me.

I did clear them and they haven't come back after a couple start/stop/short drive cycles.

With the P0447, I was checking the air filter to see if it needed replaced but I don't know if that might possibly have something to do with it. Haven't had it pop up before then. It may not play a role but in effort to trouble shoot I thought I'd mention it.

 

The alternator is supplying a high voltage, above 16 volts to trigger the P0563. Suggest you clean both battery terminals, makes sure they are tight, and test battery with a voltmeter, should be 13.6-14.4 at idle. Other codes could be related if voltage whacky. High volts can fry electronics. If no meter, most parts stores can do an intruck battery and alternator test. Can also be a loose ground strap, can bridge from negative battery post to engine block with a battery jumper cable.

 

Go to your local parts store and have the check your charging system under a full load, should be between 13.6 and 14.4 volts.
Do you not know how to check/clean or replace your air filter? When was the last major service done on this Disco?
On a side not, have you ever rebuilt or replaced your front drive shaft?

 

I'll go by and have the parts store check my charging system. My Ultra Gauge states ~13.8x volts the majority of the time, with small fluctuations. I've never seen anything north of 14v since having the Ultra Gauge, that I recall.

Disco Mike: Yes, I only brought that up because that code appeared right after I checked the air filter, when restarting the Disco. I don't have any clue what a purge canister vent valve is but it said "signal missing" so I worried I may have inadvertently disconnected it when opening / vacuuming out the air box of some small debris.

On the front drive shaft, I have not replaced it yet. I am going to get one from GB ASAP.