First time user, could use some help here...98 XJ8 VDP - traction & stabilty control lights on. Replaced control arm & DSF wheel bearing(6 months ago), got rid of shimmy... car sat for 6 months, now with new battery it drains overnight. nothing obvious staying on...is there an ECM relearn or something I am missing ? I know you can't just use a probe inbetween the terminal & cable and unplug fuses to isolate the circuits like in the good ole days.
love the car...hate the gremlins (been lots of them...timing chain tensioner, h2O pump & themo hsg, headliner...)appreciate the help.

 

Actually, yes you can.

 

Yep,- plumsause is right. You are looking for a drain of about 100 to 200 mA for some time, I believe its about 10 minutes, then it should drop to a value less than 40 mA. Of course, a battery left for 6 months can likely develop an internal shorted cell.

 

hmmn-I had read somewhere that b/c of the complexity of all of the Micro processors & relays that you can not use that method. Any suggestions as to where to start or if there is any kind of relearn that is required? I am tempted to drive it for a few miles for a test, but I now don't have any confidence(again)...and I don't know if it will go into a limp home mode (I work 60 miles away- a little too far away for the gamble!)
thanks for your response.

 

Well, I would first get the battery charged - either by running the car for 10 to 20 miles during the day, hanging about the neighborhood, or a few hours on a lower than 15 amp charger. Then check the battery voltage both running and stopped, then stopped with the headlights on. Then I would wait ten minutes to allow the security system to settle, remove the battery ground lead, only because it is easier to grt to, then connect a DMM with the leads set for current, 0-10 amps. Put the leads inthe circuit with the positive leag towards the body ground and the negative lead towards the battery, After you have confirmed less than 1 amp, switch leads and range to read 0-100 mA and monitor current. Get the trunk lamp out- method up to you- and look for 30 mA or so. If higher, pull fuses and see where the power is going. I am sure I left something out, but that should get you started without screwing up the car or the meter.