Thoughts on battery or alternator?

[reb78]

What are folks thoughts here?

2007 Discovery 3 2.7V6 auto.

The other half reported EPB fault messages flashing up on the dash today - twice. They disappeared and nothing more than that on the dash.

I plugged my Hawkeye in this evening - EPB had a fault code logged C1A00 - ECU Internal Failure. Circuit Voltage Above ... I forgot to take a photo of the ... before i cleared it!

This seemed odd as the EPB is working correctly.

This model does funny things when the battery is faulty. Battery isn't that old but came from my L322 which had been parked up when the previous one in the D3 failed.

I looked at the voltages on Hawkeye. After sitting for 5 mins after running the battery as at 11.7v. Started up and the voltage is 14.1 on Hawkeye. I didnt measure with a voltmeter across the battery terminals tonight as didnt have time but both of those seem low?

Lot of short journeys recently but at least a 1.45 hour round trip before those measurements.

I'd say its 'just' the battery but the alternator output seems marginally low too? I might stick the battery on the charger in desuplhation mode and see if that makes much difference tomorrow but what do folk think about the alternator? I can stick a voltmeter on tomorrow and see what the readings do if i load it up running.

 

[Trevorleach]

My D3 alt pretty much runs at 15v all the time, after an hrs solid run it might drop to 14.5v.
They certainly love a battery.
Ign and interior lights on with engine off = flat battery pdq.

 

[m_c]

That age may have smart charging, in which case the charging voltage will vary quite a bit.
@Ubique can probably confirm..

 

[reb78]

That age may have smart charging, in which case the charging voltage will vary quite a bit.
@Ubique can probably confirm..

I did wonder. But thought if the battery was low at 11.7v the alt might put out more rather than less than 14.4v?

 

[m_c]

If it does have smart charging, voltage can usually sit anywhere between 13.5V and 14V at idle, and might not rise much higher for a period of time and until driven, to give the battery time to recover from starting.
At 14.1V, the battery will still be getting charged, just not as quickly as it possibly could, as smart charging also takes into consideration how hard the alternator can be pushed to avoid overheating it.
At idle, alternator cooling is marginal, so if you try pushing it to hard, they can be quite easily overheated. Letting a non-smart charge alternator sit at idling to charge a flat battery is one of the worst things you can do to an alternator.

 

[reb78]

If it does have smart charging, voltage can usually sit anywhere between 13.5V and 14V at idle, and might not rise much higher for a period of time and until driven, to give the battery time to recover from starting.
At 14.1V, the battery will still be getting charged, just not as quickly as it possibly could, as smart charging also takes into consideration how hard the alternator can be pushed to avoid overheating it.
At idle, alternator cooling is marginal, so if you try pushing it to hard, they can be quite easily overheated. Letting a non-smart charge alternator sit at idling to charge a flat battery is one of the worst things you can do to an alternator.

That's interesting.

A few posts on AULRO suggest that the voltage I am seeing from the alternator is ok. I'll take the battery out and give it a.proper charge tomorrow.

 

[Trevorleach]

PWM signal controls the alt.

 

[Ubique]

That age may have smart charging, in which case the charging voltage will vary quite a bit.
@Ubique can probably confirm..

Disco3's have 'smart' charging in that the voltage varies with temperature, it doesn't have a BMS so can't / won't drop the charge voltage once the battery charge state is >80%. Also check that the external temperature displayed on the dash isn't showing a spurious value (-40 deg. C. is the default value) as this can affect the charge voltage.
The Disco3's were originally equipped with Lead-Calcium batteries that require a high (>15VDC) charge voltage at low temperatures, for some other types of batteries (Flooded, EFB & EFB+) this voltage is too high and will lead to gassing & a shortened battery life, so if you replace the starter battery, then fit an AGM type - I wouldn't recommend a Pb-Ca, neither do JLR.

 

[reb78]

Ok, so the voltages on Hawkeye may be misleading.

At the battery terminals, I get 12.85v when its been off for a couple of hours and turn it on and it starts at 15.45v decreasing a little to just under 15v at 14.7/14.8 after a short while.

So seems to me that the battery and alt is ok.

The fault code is back again - the full code was C1A00 - ECU Internal Failure. Circuit Voltage Above Threshold - google doesnt throw much up on this. This thread comes up - https://www.disco3.co.uk/forum/topic104842.html which also suggests alt or battery but the figures on mine seem fine. Any ideas?

This is on one of the RR forums re this fault code:

Control Module -Circuit voltage above threshold
• Vehicle dynamics control module power supply circuit voltage above threshold
• Charging circuit fault
• Defective or flat battery - Check the battery voltage and charging system. Refer to the relevant section in the workshop manual. Refer to the electrical guides and check the power supply circuits to the module.

The EPB switch did play up a few months ago - could that be related?

 

[Trevorleach]

Disco3's have 'smart' charging in that the voltage varies with temperature, it doesn't have a BMS so can't / won't drop the charge voltage once the battery charge state is >80%. Also check that the external temperature displayed on the dash isn't showing a spurious value (-40 deg. C. is the default value) as this can affect the charge voltage.
The Disco3's were originally equipped with Lead-Calcium batteries that require a high (>15VDC) charge voltage at low temperatures, for some other types of batteries (Flooded, EFB & EFB+) this voltage is too high and will lead to gassing & a shortened battery life, so if you replace the starter battery, then fit an AGM type - I wouldn't recommend a Pb-Ca, neither do JLR.

I was under the impression 15v charge rate was to high for an AGM battery?

 

[Trevorleach]

Ok, so the voltages on Hawkeye may be misleading.

At the battery terminals, I get 12.85v when its been off for a couple of hours and turn it on and it starts at 15.45v decreasing a little to just under 15v at 14.7/14.8 after a short while.

So seems to me that the battery and alt is ok.

The fault code is back again - the full code was C1A00 - ECU Internal Failure. Circuit Voltage Above Threshold - google doesnt throw much up on this. This thread comes up - https://www.disco3.co.uk/forum/topic104842.html which also suggests alt or battery but the figures on mine seem fine. Any ideas?

This is on one of the RR forums re this fault code:

Control Module -Circuit voltage above threshold
• Vehicle dynamics control module power supply circuit voltage above threshold
• Charging circuit fault
• Defective or flat battery - Check the battery voltage and charging system. Refer to the relevant section in the workshop manual. Refer to the electrical guides and check the power supply circuits to the module.

The EPB switch did play up a few months ago - could that be related?

Battery standing voltage of 12.85 is in my opinion to high, I would say it has a fault or will have soon.
Might be worth checking standing voltage after it has sat asleep all night?

 

[Ubique]

I was under the impression 15v charge rate was to high for an AGM battery?

15V is knocking on the ceiling, but not excessive. AGM's also like raised charge voltage in the cold, which is when you'll get that from a Disco3 - and JLR specified AGM's as a direct replacement for the Pb-Ca, and I'm sure they have better people than me making those sort of engineering decisions.

 

[reb78]

So, my issues appear to be worsening.

Today, the EPB fault flashed up lots on the dash on a short drive and then it became accompanied with the amber suspension light and gave the following fault codes:

C112F - Air spring valve actuator stuck open, actuator stuck open
and
C1130 - Air spring air supply. Signal has too many transitions/events

All of this seems to have started since I changed the front suspension arms. Does anyone know if wiring common to these two systems runs in the front passenger footwell? I think some of it is there and am wondering if i have disturbed something when doing the top arms and removing the plastic arch liner?

Other ideas welcome as i am at a bit of a loss now and cant see how these are connected (if they even are that is!)

 

[JOEPRO]

You need to have the battery properly load tested. Voltage alone doesn't tell you the whole story. Take the car to a local autoparts place with a drop tester. Battery needs ruled out first, and it has not been ruled out until it's load tested.

 

[Trevorleach]

Suspension Height Sensor Connector Plug Fits Land Rover Discovery 2 3 YMQ503220 | eBay

Until now, the only solution to this problem has been to replace the complete Chassis Harness or use Land Rover's Harness Repair Kit - YMQ503220. The Land Rover Harness Repair Kit - YMQ503220. Discovery II TD5 and V8 (with SLS).

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[willie.macleod]

So, my issues appear to be worsening.

Today, the EPB fault flashed up lots on the dash on a short drive and then it became accompanied with the amber suspension light and gave the following fault codes:

C112F - Air spring valve actuator stuck open, actuator stuck open
and
C1130 - Air spring air supply. Signal has too many transitions/events

All of this seems to have started since I changed the front suspension arms. Does anyone know if wiring common to these two systems runs in the front passenger footwell? I think some of it is there and am wondering if i have disturbed something when doing the top arms and removing the plastic arch liner?

Other ideas welcome as i am at a bit of a loss now and cant see how these are connected (if they even are that is!)

You are right in thinking that related wiring to all the systems you are having faults with runs right next to where you were working, look for three large plugs/sockets attached to the outside of the passenger footwell inside the wheelarch liner. Worth pulling the liner to double check the wiring.

 

[reb78]

You are right in thinking that related wiring to all the systems you are having faults with runs right next to where you were working, look for three large plugs/sockets attached to the outside of the passenger footwell inside the wheelarch liner. Worth pulling the liner to double check the wiring.

Thanks for this. It's the only link I can think of and the more I read, the more I think all the wiring runs there. You dont happen to.know of a link describing the connectors do you? Been searching tonight but no luck yet.

 

[dave h 2]

AGM batteries are also spec'd for 4x4 due to the no spill feature for off road

 

[willie.macleod]

Thanks for this. It's the only link I can think of and the more I read, the more I think all the wiring runs there. You dont happen to.know of a link describing the connectors do you? Been searching tonight but no luck yet.

Easy enough to find, if you've had the wheelarch liners out before then should be quick enough to get access to. Bottom pic is the one you want.

 

[sako243]

Thanks for this. It's the only link I can think of and the more I read, the more I think all the wiring runs there. You dont happen to.know of a link describing the connectors do you? Been searching tonight but no luck yet.

You can subscribe to Topix on a day by day basis if you want @reb78. I think the last time I did it was ~£12/day. Seems steep but when you consider it's the JLRs full blown workshop and maintenance manuals specific to your vehicle it's a bit of a bargain as everything is click through and provides all the electrical pin outs and so on.

Of course one could use or write a scraper to grab everything possible whilst you have access