2002. P38 4l thor/motronic. ABS, TC lamps

Hello again. I'm seriously stuck with this one. I've carried out every task advised on this thread, thanks all. In addition I've renewed the abs pump. Still, nanocom shows no faults for WABCO. Am I correct in the belief that the alternator deals exclusively and independently with charging? Or could there be an electrical fault of some type interfering? I ask as many have gone for battery/alternator issues. I renewed the battery before coming away but I have a high pitched whining coming from the alternator. Not loud but audible from the cab. Anything, anybody, please. Thanks in advance. P.

Have you checked the brake light switches - doesn’t always flag a full DTC - there’s sometimes a fault stored in the error memory which is separate from the DTC memory and can be read with T4 but not sure of other diagnostic kit capabilities

The brake light switches are renewed and only yesterday I readjusted. Btw. I see rave mentions earthing points I may have missed on my connector blitz.. somewhere near the abs pump? Got my scruff on ready to go. RE bleedthe abs system

System. (My thumbs are too clumsy for this moby). Also I went round all the axle nuts which are tight. Thanks for the prompt response. I am hoping that someone will join in with more ideas.

Is the battery good ,,A whining alternator can be a sign its struggling against a bad celled battery,.There might be enough to start it but the power drop on start up can leave faults on the message center when you switch off.. Even new battery's can fail,Just a though...

I'm beginning to agree with you. 11.something after a short standing. Would you believe I carry a spare alternator. That whined. I'll switch batteries later. Thanks again.

Is that 11. something volts if so battery is well and truly shot .

supapete said:

I'm beginning to agree with you. 11.something after a short standing. Would you believe I carry a spare alternator. That whined. I'll switch batteries later. Thanks again.

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11 volts means the battery is probably shot. Whining from the alternator may be bearings but can also be failing field windings.

This is me all over! I must've done something terrible in a previous life. Because of being high and dry on previous trips, belt and braces, I put a new battery in the car and the caravan. Guess what. A duff battery. Where to get one here......................... I'll report back. Thanks.
.

Carsvan battery wouldn't physically fit so i disconnected the connectors and put jump leads onto the connectors not the car battery. Connected the caravan battery still abs TC lamps on. When I reconnected the car battery the TC lamp went out. We're an hour in front of you but it's still too early for this. Regards P.

supapete said:

This is me all over! I must've done something terrible in a previous life. Because of being high and dry on previous trips, belt and braces, I put a new battery in the car and the caravan. Guess what. A duff battery. Where to get one here......................... I'll report back. Thanks.
.

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What's the battery and what's the set point on the alternator? Duff alternator would kill a battery but so will too low a set point for a calcium one.

I can't pretend to go any way to understanding the questions without much more learning. I can only add that iveI changed alternators with the same outcomes. The TC lamp is still going out. I'm reluctant to drive it in case it stays on. Whilst it's out ,in my tiny mind, I thought there may be some diagnosis suggested. But many many thanks for sticking with this. Regards P.

What volt`s are you getting at 2000rpm with everything turned on, that will tell us the set point of the regulator and how good the alt is.

Bit of an outside chance,,With you disconnecting and reconnecting the battery terminals ,maybe a slight ill fitting ,or bad positive or earth wire and you have disturbed it for the better..........

11.48v all off, 14.26v tickover, 14.06v all on tickover, 14.03v all on 2000rpm. That's with my "spare" alternator. I posted the voltages with my new alternator on page 1. The TC lamp is still going out ! Dare I drive it round the block? Could the change of battery have wiped out a residual fault? Got a battery on order anyway. Guess when its coming. Si ! Manana. Regards P.

On the motronic page, nanocom I'm getting Pxxxx=permanent voltage supply fault drive cycle A. Occurred 1 times. Signal too low
Fault is not currently present.
This is the only fault I'm getting anywhere. P

As others have said (I think 11.48 at rest with all off) is effectively a dead/dying battery.
Your battery from page #1 is better than the battery you have on it now.
Your tickover volts seem a bit low to me (i get 14.6v on my 4.6 Thor Motronic) with everything off and 14.3 with everything on.
But, as you say a new battery is en-route.
On my previous 4.6 Thor I would get lots of spurious TC/ABS etc. warnings because the battery was knackered and the Alternator was not coping either.
One both were refreshed all the warnings just went away and never came back.

Hi Supapete , battery on should show 14-2 on average of all motronic 4.6 , so you assume battery ok for now till new one arrives , ok so heres a shot in the dark , does the becm go to sleep at night when you park up and lock it ?????? do you know how to check this ???? im assuming you do as you have owned previous p38 4-6s cos this if not gone to sleep will drain battery !!!! ok only trying to help ,regards Mozz

As @Saint.V8 would say, rule number 1) have you got good volts? Rule 2) go back and read rule 1 again!

That battery should be up near 12.9V before you start. Until that is the case you're chasing ghosts. On rr.net and maybe here somewhere there's an electrical troubleshooting guide. The GEMS is more renowned for earth issues but that doesn't mean the Thor cannot have them.

Grrrrrr said:

As @Saint.V8 would say, rule number 1) have you got good volts? Rule 2) go back and read rule 1 again!

That battery should be up near 12.9V before you start. Until that is the case you're chasing ghosts. On rr.net and maybe here somewhere there's an electrical troubleshooting guide. The GEMS is more renowned for earth issues but that doesn't mean the Thor cannot have them.

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You would be lucky to see 12.9 volts except just after turning off, 12.7/12.8 after an hour or so depending on the state of charge and condition of the battery,