Had my 2006 parked for a couple of weeks while I drove my XK8 convertible. The convertible just went back to the body shop to fix a failed paint job so I took the X Type out to run errands. Got a check engine light and the motor stumbled when I tried to accelerate. I found if I took it easy I could still carry on and the more I drove the better it got. I cleared the codes with a cheap OBD2 reader - except for the check engine light (my good OBD2 reader is in the convertible in town, a ferry ride away). I actually managed to get the car up to 120 kph no problem, so I plan to take the car to a nearby town and try the fixes suggested in this forum this weekend. I will grab some octane booster this morning and see if that helps. This weekend I will remove and clean the TCM and seal it with foil tape and sealer. It was running brilliantly all spring so I find it a bit odd for this to appear after just sitting for a bit. Certainly, I look forward to suggestions and comments here. I will pick up my good OBD2 reader in town today and see what codes are showing.

 

Battery? Battery? Battery?

What was / is the standing voltage?

Did you read the codes before clearing and resetting CEL?

f so, what were they?

I applaud your use of the generic OBDII tool . . . I have a cheap ELM in each car along with an el cheapo ex smart phone and save my Mongoose for the workshop. However, for so many hundreds of similar cases caused by sagging battery voltage, I do believe a far more useful tool are the new generation of cigar socket USB chargers that have a bright visual LED readout of the standing battery voltage, typically 12.6V prior to start; then 14-5V when running (alternator recharging battery); finally 13.0V when still running but alternator has done its job and battery is fully charged. Ebay is awash with latest Chinese offerings . . . generally under $5 but I managed 6 for $15, posted direct to my door in Australia.

With a fleet of infrequently used cars, all now maintained on smart chargers, and backed up with instant visual readout of battery condition because I have had instances where an electrical blackout has failed to reset a smart charger. One instance saw me successfully start the S-Type at 11.7V but with every fault known to mankind. The X-Type can be a tad more forgiving, but not much. Now, DTCs with or without CEL is now a rarity.

Hence, my questions and your feedback will guide further help. I am inclined to believe that doing nothing other than a full charge, followed by ample drive cycle will see your symptoms disappear . . . but watch that battery, as it may be signalling the end is nigh.

Best wishes,

Ken

 

Well, I got in the car and it started up and all the lights went out. It ran normally - that means great - all day. I did put a bottle of octane booster in this morning but really, it didn't seem to need it. I did also purchase a roll of foil tape and spent some time sealing the area at the bottom corner of the windshield where it tends to leak into the cabin and onto the TCM.

 

So . . . welcome to the world of a FLAT Battery.

Great to hear you are fully mobile again . . . but if this is just an occasional drive, I do suggest you fit a small smart charger.
The alternative is that this will recur, shortening life of your battery by more than the charger costs.

Glad to have helped,