I have a real problem with my 2009 XF diesel, (85,000 miles). Initially, the car appears to go through the cold start procedure, but the glow plug light doesn't come on, and the system then goes back into 'standby' and I have to repeat the procedure. I was advised to disconnect the battery leads, and join them together for a few seconds, then replace them, and finally after two more attempts it started. I then got the car to a Jag specialist, and the diagnostics indicated a new battery required. Fitted the new battery, and all was well for a couple of days, but then the same problem occurred. I got someone out to me with a diagnostic tool, and this time it threw up a fault code as follows: POA09 DC/DC, with the added message: Converter status. Circuit low input.
I have contacted Jaguar regarding this, and as yet they don't know what it means!! How bad is that? So my car is currently sat on my driveway awaiting a 'doctor' who can diagnose a cure. Anyone out there with a suggestion?

 

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Can you get the car running if you jump it? Did you verify the alternator is charging the battery? You should see 13-14 volts at the battery when it's running. If voltage drops to low you'll have all kinds of of electrical issues popping up.

 

Thanks for the reply, at present cannot get the car running, if it ever does start then I agree, I need to check if the alternator is charging. Problem is, it's a new battery and I gave it an overnight charge just to make sure it would be up to scratch. I've a sneaky feeling there's an ecu fault somewhere in there, but if Jaguar don't know how to cure a fault that shows up on their diagnostics, what chance have the rest of us got?

 

I know the XF does have some issues with battery drain when the car is off. Maybe try unhooking the battery and charging it for a while and then reconnect the terminals to start it.

 

Thank you for your suggestion, I have tried this once when I replaced the battery, but to no avail. The real annoyance is that no one at Jaguar can tell me what the remedy to the fault code is. Surely if a diagnostic result displays - POA 09 'Circuit low input' then someone should be able to tell us where to look to put it right? Very disappointed.
On paper this car was one of the best I've bought - in reality it's the worst!

 

That doesn't appear to be an OBDII code. What type of scanner were you using? Maybe the scanner isn't giving you the correct code. Usually you can look up the OBDII code on google and roughly determine what the issue is. That code doesn't bring anything up. The description "Circuit Low Input" could mean anything. Do you notice anything odd inside the car when trying to start it? Do all the electronics work? Have you tried inserting your key into the holder? Have you tried another key (batteries bad in the key)?

 

There was a post on Fixya at the same time as the OP with the same code.
I agree it is not an OBD code and we don't know where it came from.
The Fixya reply was 'low voltage to the ECM' but, like you, I can find no other reference to this 'code'.
It would be good to see what an OBD reader says.

 

Many thanks Steve and Blackcoog for your comments. I suppose you could be right in regard to the diagnostic tool used as my nearest Jag dealer is 20 miles away so I got a local garage to check it out. Hadn't thought of the key, so I'll try the other one, and via the slot. All the other electrics seem to be in order, but on 'start up' (which it doesn't of course), the battery warning light comes on part way through the cold start procedure, then the usual 'restricted performance' orange message. Following this, the system goes into standby and I have to start again. (What's an OBD reader)?

 

O.K., got it on board diagnostics!

 

You can get an OBD reader from EBay UK - there's a huge thread on this Forum.
https://www.jaguarforums.com/forum/g...-%2A%2A-33347/
If you've got an Android phone this works
Android Torque Mini V1.5 ELM 327 OBD2 OBDII Bluetooth Car Diagnostic Scanner UK | eBay
If not so does this
U480 Car Auto Diagnostic Scanner tool OBD2 OBDII EOBDII CAN-BUS Code Reader UK en vente sur eBay.fr (fin le 28-déc.-12 08:13:42 Paris)
-I bought both from this dealer.
If your low battery light comes on then maybe the code you're getting is real - i.e. the ECM is seeing low voltage.
Have you got a digital voltmeter ?
If so check battery volts and also volts somewhere near the ECM (sorry I can't help more with where to check - I don't know this model)
It is possible that even though your battery may be good you've got an earth or supply problem preventing full battery volts getting through.
This typically causes all sorts of problems with Jaguars.

 

Thanks again Steve, the battery is fine in itself, it has been fully checked, but if there's a drain somewhere in between the battery and the rest of the circuits, then that might be the problem. Spoke to Jaguar customer services yesterday and they seemed eager to help, promising to call me back today. Received a message on my landline when I returned saying they had tried to call my mobile without success, however no missed calls on that, and I've had it with me all day expecting them to call, so don't know what happened there. Been ringing them for 2 hours since I returned, no one answering so I'll have to start again tomorrow. I'm trying to get it in to a specialist, but Christmas etc., not looking hopeful. Have to hitch a lift on Santa's sleigh probably!

 

Any luck with the other key or inserting it into the key slot?

 

Did anyone manage to get this sorted as mine is doing same thing

 

It seems this diesel is just not firing. When it gets cold enough a diesel really needs its glow plugs to work. Also, do you have winter fuel where you live, since Lancs is apparently getting a real winter once again. If it gets cold enough any diesel is going to need winterized fuel in the tank to fire properly on a cold start. Often a little petrol is blended into diesel for winter for this reason. I don't know at what temperatures diesel "antifreeze" is added but it is routine in Canada to supply winter formula fuels both diesel and petrol.

 

Problem solved at last, but doesn't bode well for the future. I knew I was going to face a hefty bill, as the car is out of warranty and the only way to get it to a Jag dealer was on the back of a transporter, costing £200 before any work was started, and Jaguar customer services said that unfortunately that part of the cost would have to be met by me, although they did say they would look sympathetically at the final repair costs with a view to partial reimbursement. So I opted to go to a local highly respected diagnostics expert, and it took him three days to find the fault. The problem was a break in the Grey/Violet wire on the main engine wiring harness, but not the type of break you would expect such as friction or trapped wire. This break was due to water ingress that had simply 'soaked through' the plastic insulation, this is a fault that the engineer is discovering now on many cars and he says it is down to the composition of the insulation, and is happening on some Mondeos that he has worked on. The position of the break was really inaccessible, being right at the back of the engine compartment and under the brake master cylinder, an absolute nightmare to get at. Once he had got to it he found green mould within the wiring, but no breaks in the casing at all, so a bit worrying for any future problems developing. I have since read on another forum that one person had the same fault, and when Jaguar checked it out, they opted to replace the whole harness rather than repair it - the cost - £1,700.00 ouch! My bill was £600.00, a lot better I suppose, but a bit of a worry if it's going to occur in a different coloured wire sometime in the future. I have since spoken to Jaguar customer services, who in fairness have kept in touch with me, and although they won't meet the cost, (understandable as it didn't go to a Jag dealership), we have reached agreement for a voucher for my next service, which I think is very commendable of them, (not got it yet though). Maybe this information will be of help to others with similar problems.

 

Hi there, I know it’s a long time ago you had your issue, but the grey and violet wire that had water damage...... what system was it connected to?