While not really "common" this is not unheard of. If you search and read other similar threads you'll find several things to investigate. We likely won't be able to tell you exactly what is causing it, you'll have to do some work based on the possible causes in order to figure it out.

 

Its a Gremlin in the Electrical system...Mine does it if I dont drive the RR for a few days. Comes up "HDC INACTIVE" then goes...last time It done it was when we had all the snow...they dont like the cold. Dont panic....just check that the HDC still works and that "CHECK CONTROL OK" is on the screen and its fine...Just the Gremlins man.

Roy.

 

If this error is occurring when you first start the car e.g. after being left for a few days then goes away once the engine has started i can 100% confirm that this is caused by a low battery problem. Land rover did a software upgrade to get rid of this message on the later models - once the error has gone away press the HDC button and make sure that the HDC light comes on the dash without any more error messages.

Matt

 

Agree with low battery issue! I replaced my battery on Monday after a week of "mysterious electrical gremlin emerging". I got the "HDC Inactive", "Air Susp Inactive", "Trans Failsafe" etc...... All that has gone away now that I have a new battery!

Go get a new one!

 

I wouldn't say its 100% the battery, but it is a strong possibility. I had random errors in the days/weeks before my battery blew up (literally). Since he indicated that the battery is good, it could be other things. It is important to check not just the voltage, but do a load test as well. Many times the voltage may seem normal until you place a load on it... and if one or more cells are shorted, then you can have the voltage dip and or not hold a charge properly.

 

Battery seems okay.
Dave

Get it tested by a professional, it "seems" OK because it starts the car, but if it doesn't provide enough juice for the various electronic modules to properly boot up (just like your home computer, they are very sensitive to power spikes and low voltage), you'll get random errors at startup - HDC faults being the most common - until eventually it'll leave you stranded without further warning. The shop you take it to should test the alternator as well just in case - they routinely do that, but ask them to make sure - to insure it charges the battery properly w/o overcharging it. My money is also on a battery on its last leg. :thumb:

 

Thank you all for the advice. I have read something before about possible battery problem as I have had the suspension inactive error in the past , although I have only had the RR for less than two months. I got the garage I bought the car from to check the battery and they said " it was okay". I have looked in the battery spyhole and it indicates that the battery is okay. I had a BMW prior to the RR and that had a duff battery and the indicator showed it was flat/requiring charging. Will have to get it checked out.
Dave

 

You might try to charge the battery, leave the charger connected and maintenance charging (trickle) and then switch on the Rover to see if you get the error. While the charger connected it should maintain a high enough voltage to start the electronics properly unless the batt is totally toast and this give you an indication whether the gremlins are low voltage induced.

 

I had my battery load tested on Sunday and it passed with flying colors. Then on Monday, after charging it and driving it on Sunday, it wouldn't start the car at all. I think there was something intermittently internally wrong with my battery. Just goes to show that a battery can "pass" a load test and still be bad. Rare, but I just had it happen.

 

The garage I bought the car from has agreed to fit a new battery on Thursday. I will update as to wether this solves all my error messages.
Dave
('54 Vogue TD6)

 

Garage fitted a new Varta Silver battery. Much better on the starting errors. Still get the HDC inactive and the lack of power steering sometimes on startup but a switch off and a restart cures that. Checked the advice from previous suggestions and confirm that I can still select HDC after the error. I'm sure the problem will get less frequent when the warmer weather comes.
Cheers for advice.
Dave

 

One Thing that you might want to check is the Speed Sensor Cables.......I had a frayed one, on my passenger side..and once I replaced it...all is well.

 

Thank you very much for the suggestion but I have no idea what or where the 'Speed Sensor Cable' is or what it does. Can you please give me some idea what I am looking for.
Cheers Dave.

 

Sure on each of the four wheels there are two sensors with cables Brake and Speed. Both have the sensors attached to the cable(just wanted to make clear that the sensor is attached to the cable for both brake and speed). So when you purchase a speed or brake sensor, you get the cable attached.

The Speed Sensor cable is the one that is connected to the Wheel Hub, it's about $118 US at the dealer, but you can get a suitable replacement from Partsgeek, or PartsTrain, for about $45 US, over the internet.

The brake pad Sensor is connected directly to the brake pad caliper, so it's fairly easy to distinguish the two. They both run along Air strut, and are held in place by clips on the Air Strut into a small housing unit which has two snaps that are fairly easy to open and close. Just pull the connectors apart and replace with new sensor and cable

I would bet that if you perform a close inspection of these speed sensor cables, you will find that one of them is frayed, and maybe being affected by dew or condensation in the mornings......my situation was very clear, and pronounced yours may be as well.

 

I'm new here and am in the middle of giving our Rangie a full service (2004 TD6 HSE) we've had the car from new the HDC has done it for years on start up and when under warranty it was'nt fixed after about 4 visits to the dealer, everything works ok it just does it on startup.
We just ignore it now

 

May be coincidence , but I don't get the HDC error on a warm day when the pre-heating doesn't come on and also don't get the error if I start the car before the pre-heating has finished. If I leave the pre-heating to finish and then start the car I seem to get the error more often than not.

 

Now you come to mention it does do this on occasion but seems to have a mind of it's own, now I'm past worrying about it and ignore it as HDC still works anyway.

 

I have looked at the sensor cables and they look fine.
Now with lots of starting experience I find that I only get the HDC error if it's cold enough for the Pre-Heating of the glow plugs to kick in and I leave that to finish heating. Now if I see the pre-heating message come on the dash, I start the car soon after the message appears and never get the HDC error message. Obviously if it is warm enough not to trigger the pre-heating then the error never happens however long I wait with ignition on before actually starting the engine. Funny cars these RR's.

 

I get 'HDC INACTIVE' error on the dash every morning on starting, but not during the day unless left for 4hrs+. Looked up in handbook and it says "A fault in the Hill Descent Control system has occurred". Can't understand why this only happens first thing but not if you stop the engine and restart it straight away. Any of you guys any ideas or have had this fault? Battery seems okay.
Dave

Probably a CAN bus error. I got this the other day when I was clearing codes with my BBS after disconnecting my battery. What's interesting is that all codes were cleared and it was still on the display. The only thing that would shut it off is if I turned the car off and on.

 

I have looked at the sensor cables and they look fine.
Now with lots of starting experience I find that I only get the HDC error if it's cold enough for the Pre-Heating of the glow plugs to kick in and I leave that to finish heating. Now if I see the pre-heating message come on the dash, I start the car soon after the message appears and never get the HDC error message. Obviously if it is warm enough not to trigger the pre-heating then the error never happens however long I wait with ignition on before actually starting the engine. Funny cars these RR's.

So you probably have an issue with the module that heats the glow plugs maybe? And it causes noise on the BUS. Which causes your error.

 

I'm new here and am in the middle of giving our Rangie a full service (2004 TD6 HSE) we've had the car from new the HDC has done it for years on start up and when under warranty it was'nt fixed after about 4 visits to the dealer, everything works ok it just does it on startup.
We just ignore it now

That sounds like we cant figue it out go away. Your took that as acceptible?

 

My car is the 2004 model of the land rover range rover and i have the "Air Suspension Inactive" warning and the "HDC Inactive" also" ABS Inactive" messages showing on my car dash. And the car cannot move from it position when gear is put in drive.
I got the delivery of EAS Activate tool and I have plugged in the EAS tool as instructed correctly and after the process the situation remain same teh fault is not cleared and my car cannot move.
Please I want to know what must have gone wrong and what I could do to resolve this new problem.

 

Luckystar, you have a whole different issue, start a new thread with this... but it sounds like you may have a communications issue between your modules. Is the EAS code a 50 - CAN bus fault?

 

Hi, I've had this "HDC inactive" error for ages now and we're going to change the battery this weekend in the hope that it helps. Where is the HDC button you're talking about though???

 

If your RR is the 2002-2005 BMW model, it is one of the two paddle switches in the center console, rearward of the shifter. The hi/low transfer case switch is also there

 

I had the same HDC Inactive message several times before I replaced the battery. It appears that the voltage drop when starting the vehicle with a weak battery triggers this message. Look at it as a warning to replace your battery before you need a jump, like I did.