Hi all,

I purchased my first ever Jag yesterday, an X Type 2.5 Auto SE AWD (07 plate). All great on the way home, but today the EML and battery lights have flashed up on the dash. I got the car home and checked the battery on a multimeter. 12.5v engine off and 14.5v engine on, so battery and alternator seem to be working fine. I used my cheap OBDII reader for the fault codes and it showed 3 - P1000 PCM didn't complete test cycle, P1647 upstream O2 sensor fault and the third code couldn't be ready by my reader. I did manage to clear the codes and the lights have gone out on the dash. I'm going to book it into my garage next week to have it checked over, but if anyone has encountered this issue before or is aware of what it might be, I would be grateful for any help. I will add that is a hot day today (~27°c) and I did have the air con on full blast. Could this be a potential cause or have I bought a car renowned for electrical gremlins? No regrets from me either way 🙂

Hi Steve and welcome.

First suspect would be a flat battery. Do you have any idea how old it is? A low battery charge is quite capable of throwing all sorts of fault codes and as the codes have not re-appeared that sounds the most likely cause. If you checked the battery just after you got home it may well have indicated a reasonable state of charge. I would give it a full charge and see how it goes.

Only really serious problems are usually to do with rusting sills but there are replacements availble to weld in (Mine has been done and is covered in lanogaurd to keep it rust free.)

Good luck

John

Hi John,

Thank you for the welcome and for taking the time to offer your advice. I'm not sure how old the battery is, it doesn't look very old but it is a brand I've never heard of - Point S (I've attached an image).

I've been out to the shops tonight in the Jag and the EML has come on again (same codes) but no battery light.

I'll have my garage run the diagnostic on it next week, but I think a new battery is a good idea.

Noted on the rotting sills - I'll keep an eye on mine.

Thanks again, Steve

Hi Steve.

FYI The P1000 PCM code can be thrown by a battery disconnection, or possibly low voltage and needs a Drive cycle to be completed to allow the Power Control Module to reset.

Drive Cycle Instructions are normally to drive until everything is warmed up and use all the gears with a fairly aggressive right foot. Then leave the car overnight and hopefully it will have reset itself.  

The P1647 upstream O2 sensor fault refers to a sensor in the exhaust monitoring the Catalytic convertor, so probably worth getting a proper diagnostic on that whilst you are at the garage to avoid damaging the cat.

Good luck 

John
BTW the sills you can see from the roadside are plastic covers. The scarry bits are underneath 🙂

Hi John,

Thanks again for all of your advice. The Jag has been to the garage and they have done a full diagnostic on it. They found a short circuit in O2 sensor control module bank 2 sensor 1. The previous owner had replaced this sensor, but with a cheap aftermarket part. I have had an OEM Denso sensor fitted to replace the faulty sensor and all is well. Drives like a dream and you wouldn't tell the car is 18 years old as its immaculate inside and out. Tax and fuel costs are a little steep, but the smiles it gives me are well worth it 😁

Cheers,

Steve