It's used while the vehicle is in transit from the factory then disconnected by the supplying dealer - not part of your problem.

 

Well back to the old drawing board here. Ok. Car was being a ******* here so ended up buying an asi throttle body. Hard reset. Etc. car now is doing all sorts of weird stuff. Ok I'm gonna try to explain this best I can.

I can drive around fine for about 15 mins. Then bam fail safe, gear box fault, asc failure etc. this is where it gets weird. I can sit in the driveway letting it run. It will throw all kinds of weird messages. I get the fail safe etc. get a low brake fluid warning, abs light, the circled explanation mark all completely randomly whole it sits and idles in my driveway. I am not getting a p1121 code any more but I am getting p1623 from the TCM. P1623 comes as badically an alternator code. I have ~13.97v at the battery, the fuse box by thr front passenger tire and by the front drivers headlight. Nothing from the abs module or ECM. I wasn't getting anything from the abs module while the abs light was on intermittently. I am at a complete loss here.

I will throw one more thing out there. I have noticed that on the few days it has worked properly the volt meter in the dash reads a perfect 13. Right now and every time it screws around the volt meter in the dash reads a **** stars pubic hair below the 13. Before I bite the bullet and get prison raped by dropping it off some where to get looked at what should I be looking at?

 

Did you try replacing that five-year-old battery yet?

 

Ye I replaced the battery with 1200 amp one. When that didn't fix it I had them both tested. Both passed.

 

Open the cover to the driver side fusebox at the end of the dashboard. Disconnect the battery for safety. Check the the B+ cable is firmly bolted to this fusebox and there is no corrosion. Also re-seat the relay in this fusebox and check and re-seat fuses 14 and 18. Reconnect the battery and see if you still have the problems.

 

Ok I will throw out everything I've done here. I have reseated every relay, checked and reseated every fuse in every box. I have cleaned grounds in the box where the ECM/TCM is, brake booster/ master cylinder, below the fuse box by the abs module, in the trunk. I have cleaned up the positive side wiring. In the trunk by 250A fuse, where the ECM is, the fuse box by the abs module. Everything I found was in good shape but I did it any way with no change. I swapped out "warm" relays with brand new ones. I have pulled each individual wire out of the tps connector cleaned reseated in the connector and plugged back in. I have 5.00v on the top (#4 pin) wire to the tps while the car is running.

I am now getting p1222 code. Pedal position sensor code along with the p1632 code. I don't know if this is a matter of adjusting the tps or my asi throttle body is no good. I am at a loss for words here.

 

You have a 2000...it is a prime suspect for this TSB which can cause many of these symptoms: http://jagrepair.com/images/TSB/XK8/...%20failure.pdf.

It is definitely worth checking. Be sure to disconnect the battery when removing the instrument cluster and rotate the locking bails so the connectors are drawn in fully when you re-seat the two connectors.

After inspecting for the TSB, if still no luck, remove the ECU, open it up and inspect it for leaking electrolytic capacitors (signs of wetness, corrosion, or black and brown spots)

 

I will look into this tsb and pull it apart when I have a chance again. Now one more thing to this puzzle is that the Ecu was replaced in December by the dealer and is still under warranty so I will not be pulling it apart. Also the tsb goes up to a05332. My car is a092xx. Could very likely be the problem still. Manufactured daye is may 2000 if that helps

 

While you have the instrument cluster out, also inspect the solder joints on the larger components (connectors, electrolytic capacitors, etc). They are most prone to break a solder connection due to their weight. Also check for capacitor leakage on the instrument cluster.

The instrument cluster computer acts as the communications hub for all the data links in the car. Multiple random failures have been seen due to power supply problems on this board.

 

Stupidest question ever. After reading through the tsb only one (really stupid) question. I honestly don't know how to scope the steering wheel out and down. Mine comes out and down to a nice spot as soon as I stick the key in the ignition.

 

There's a control on the left side of the steering column. Acts sort of like a joystick to control steering wheel position. Also a manual/auto setting there. Appears you're set for auto currently.

 

Ripped the cluster out today. Should note that my cluster was replace in 2003 noted by the sticker on the back. It also looks different in the area noted in the tsb. Those soldering joints are not there. Also my car does not have any of the mentioned paper between the circuit board and the back plate. Nothing visible from the back side everything looked alright

Should also note that I am getting p1797 now the TCM and ECM are not communicating. Seams it goes out for a second every few minutes and comes right back.

 

The question...
I've been meaning to dig a little into this "battery state of charge" issue in regards to intermittent failures like this thread's subject. These modules are constantly powered, either with ignition ON, or OFF, meaning that with ignition OFF they are powered strictly by the battery. So, the question is, will exposure to sub-par power while ignition is OFF affect the module's function later when it's switched to the alternator's 14 volts?

The bitching...
If this is, indeed, the case it has to be, yet, another design disgrace. Since when car components go haywire just because the battery is not at full charge? Say, the radio on an 80's Mustang is shut down after ten minutes driving because the battery charge was low a couple of hours before. How stupidly insane and retarded would that be? It is hard to believe how many of these annoyances were designed to fence off the owner/driver and actually trigger major incidents, such as, say, limp home mode 120 miles from home on a Saturday night with everybody in the car. Why not a toggle switch on the dash that kills that system for now and lets you drive home "under the severe risk to the family for actually driving the car without a system that comes in to use for a couple of seconds when a wheel spins". You read all these horror stories right here in our Forum about these early V8's operational problems and it's just so sad and, worse yet, with such a number of ambiguous resolve actions that unfortunately tarnishes so much the image of an otherwise highly desirable car and to the point of making you feel guilty when selling this "package" to somebody else.

OK, that's enough...

 

Not gonna lie to you forced air. If and when this thing is up and running again it will likely have a for sale sign in it and once it's gone never look back