[Dirtydthedefender]

Hello, I have a 2007 Discovery 3 HSE 2.7 TDV6. Recently, when I come to the car, the battery voltage is at 14.6V. When I start the car, everything is normal and the air suspension goes up fine. However, while driving, I get a HDC fault stating special programs are not available. The suspension then lowers and the battery reading drops to 13.1V. I recently had a wheel speed sensor go on the front left, which I replaced with OEM and my scanner detects it fine. Does anyone know what to do? I am getting a lot of lights on the dash and I suspect it might be an alternator problem, as my battery is correct and tested fine.

 

[lynall]

So the battery has 14.6 volts before you start the engine?

 

[Dirtydthedefender]

No sorry it 14.6v started then drops to 13.2 13.1v after fault and suspension lowers it sits at 12.2v when engine not running

 

[Dirtydthedefender]

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[lynall]

No sorry it 14.6v started then drops to 13.2 13.1v after fault and suspension lowers it sits at 12.2v when engine not running

The D3 can run up to 15.2 volts when it needs to, generally higher charge rates means the battery is on its way out.

 

[TheMunster]

You need to read the codes, the battery voltage readings are probably innocent, its higher when the battery needs to recover from starting the car but lowers when the battery gets charged. Anything from a height sensor to a wiring fault could be causing this. Playing parts darts with these cars is expensive.

Edit - 12.2V is a dead battery, needs a recondition but more likely replacing.

 

[Dirtydthedefender]

You need to read the codes, the battery voltage readings are probably innocent, its higher when the battery needs to recover from starting the car but lowers when the battery gets charged. Anything from a height sensor to a wiring fault could be causing this. Playing parts darts with these cars is expensive.

Edit - 12.2V is a dead battery, needs a recondition but more likely replacing.

Would this corse the suspension to lower and hdc faults on the dashboard I have had the battery tested and told its ok so when I start the car everything works fine and it’s charging at 14.6v then after driving it it drops to the low 12v I was thinking could the air compressor be on its way out and staying live Ino d3s are sensitive to voltage are give U codes

 

[Dirtydthedefender]

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[lynall]

Would this corse the suspension to lower and hdc faults on the dashboard I have had the battery tested and told its ok so when I start the car everything works fine and it’s charging at 14.6v then after driving it it drops to the low 12v I was thinking could the air compressor be on its way out and staying live Ino d3s are sensitive to voltage are give U codes

If it is dropping to lo 12volts whilst driving then I would say you have an alt problem.
I have never seen mine go under mid 13volts.

New alt must be Denso (I think) anything else will cause issues.

 

[Dirtydthedefender]

If it is dropping to lo 12volts whilst driving then I would say you have an alt problem.
I have never seen mine go under mid 13volts.

New alt must be Denso (I think) anything else will cause issues.

Thank you for the reply does any loss in power (v) corse the problems I’m getting I’m getting told battery ,alt ,hight sensors ,air compressor problems ,wheel bearings

 

[lynall]

Thank you for the reply does any loss in power (v) corse the problems I’m getting I’m getting told battery ,alt ,hight sensors ,air compressor problems ,wheel bearings

Low volts causes all sorts of problems, d3 are well known for alt issues causing special programme and suspension issues.

I can tell you during the winter mine runs high 14s to low 15s, summer high 13s to mid 14s, and it has been that way for 11 years.

 

[Dirtydthedefender]

If it is dropping to lo 12volts whilst driving then I would say you have an alt problem.
I have never seen mine go under mid 13volts.

New alt must be Denso (I think) anything else will cause issues.

Thank you for the reply does any loss in power (v) corse the problems I’m getting

 

[lynall]

Thank you for the reply does any loss in power (v) corse the problems I’m getting

Sadly that is an open ended question on the d3, low vs causes multiple issues, only way to be sure is new alt and maybe new battery.

Always worth popping over to the disco3forum and doing a search for your issues, think need to sign up to search, but well worth it.

The alt is told what to do/charge by the engine ecu via a pwm signal, so not straight forward like a std alt, hence my earlier comment to make sure you get a decent one as a cheapie will put you right back to square one.

 

[Dirtydthedefender]

Sadly that is an open ended question on the d3, low vs causes multiple issues, only way to be sure is new alt and maybe new battery.

Always worth popping over to the disco3forum and doing a search for your issues, think need to sign up to search, but well worth it.

The alt is told what to do/charge by the engine ecu via a pwm signal, so not straight forward like a std alt, hence my earlier comment to make sure you get a decent one as a cheapie will put you right back to square one.

Ye il go over there mate and see if I can find anything mite just have to be a new alt and battery to rule them out thanks again mate for your help