My XType has been at the repairers for the last 3 months (waiting on parts). I only just got it back - I assume it hasn't been run in all that time so the battery might have taken a hit. When I drove it home yesterday from the repairers - about a 20 KM journey it performed faultlessly. However when I took it to the shops today it started running rough and the check engine light started flashing, then stopped after about 5 seconds. I put my OBD code reader on it afterwards and got the P1000 code by itself. Reading up on this code it says it is related to disconnection of drivetrain ECU or battery. Do you think it might be time for me to get a new battery? Or could something else be at fault? I'm confused because I had my car serviced yesterday and they reported the battery as being weak, but it starts just fine without labouring and the battery indicator window is green saying "OK" - it is not in the black ("Charge needed", nor red (replace). So is my battery causing the stumble or do I look elsewhere?

 

Don't rely on generic code lookups as they are often misleading.

You will ALWAYS see either P1000 or P1111:

P1000 : all engine management OBD diagnostic monitor drive cycles HAVE NOT BEEN COMPLETED.
P1111 : all engine management OBD diagnostic monitor drive cycles HAVE BEEN COMPLETED.

I'm surprised there are no other stored or pending codes after the CEL had illuminated. However, as you have already been advised the battery is weak, it could be a good time to replace it. A partially discharged or failing battery often caused all kinds of weird electrical behaviour on Jaguars.

Graham

 

The thing I don't get is the battery light is not illuminating at all - I would have thought if it was my battery causing the issues it would be lighting up....? I think I'll replace the battery anyway just to eliminate that variable, like you said the workshop reported it as weak, and battery issues can have other flow on effects in the electrical systems (including ignition I assume..).

 

It's monitoring the alternator output not the battery.

The charge indicator (red) warning illuminates when the is starter switch is turned on and should extinguish when the engine is running. If the indicator remains illuminated when the engine is running it indicates that there is an alternator fault.

Graham

 

WOW!! I haven't seen (or heard of) a peephole on a battery for years and years (at least here in the U.S.).

 

Drove to the shops again, this time the check engine light went steady after flashing for a while - the engine missed for a while then came good but the CE light stayed on. Checked for codes got P0306, P1314, and P1000. The codes seem to be related to cylinder 6 misfire and cat damage. I'm going to replace the battery and then clear the codes. Hopefully a battery change is all that's needed.

 

Flashing MIL can cause massive damage in a VERY short time. Like a couple of blocks!

 

You have put the fear of God in me. I was going to drive to the local battery installer but now I have thought better of it. I have organised with Battery World who come to you (at cost of $45 BH, $85 AH) to come and install it. I have it booked during business hours as I am currently working from home.That way I won't be driving the car anymore (minimising damage) until I get the battery installed on 1 Sep (Payday!). Hopefully after it's installed my car will run as normal again after I clear the codes. If it throws codes after the new battery install I will not be happy!
They offered me two classes of batteries, given the finicky nature of these X types I have bitten the bullet and opted for the higher spec, more expensive one - $320 AUD, plus $45AUD home install fee. It has longer warranty than the lower spec battery as well 48 as opposed to 36 months.

 

****! They saw you comiing....

 

With a Jaguar, spending time before spending money is always the best approach to troubleshooting. Generally, a code on one cylinder only is electrical whereas multiple cylinders (especially on the same bank) is usually fuel related. However, there always examples of exceptions to this!

We've already covered P1000 so here's the JLR DTC lookup for P0306 and P1314 with possible causes:





I don't know your time commitments, facilities or tools availability but here's how I'd approach the issue:

1. fully charge the battery
2. swap coil on cylinder #6 with any other cylinder
3. cross fingers
4. run engine again

If the CEL doesn't illuminate, it's likely just a bad battery issue. If it does illuminate and the P0306 persists, it's not coil failure. If there's a P030x (where x is 1, 2, 3, 4 or 5) code for the cylinder where you put the coil from cylinder #6, then it's a bad coil.

Graham

 

Yup, what he said ^