Hi everyone, New issue with the Jag....

Car has been running fine but suddenly the battery power only lasted for the car to get out of the garage, then stopped in the driveway, battery was almost flat and had to be charged for the rest of the day and night.
Next day drove the car for about an hour and then parked it. day after that, same story not even starting. Battery is 2 years old, Alternator is a replacement Denso, also 2 years old.
Car has not been driven much last 2 years.

Alternator is charging with about 14 volts when car is running.
Power draw when car has been shut down for about 20 minutes is 0.03 Amps.
Battery seems to charge fine, CTEK smart charger charges all the way to "Green"
Battery passes test cycle with basic battery tester. Load test has not been done, have ordered an old style load tester.
Will check the voltage later today some hours after topping up the battery with the charger.

So possible problems are:
The Battery is bad
Or The alternator is bad and reverse pulling all the power out while running (broken diodes)?
Or Something is using A LOT of power but only when the car is running.

Any ideas???
Kind regards

 

I'd expect a dead battery under load. Most ones I've had fail on cars & bikes still show a good voltage but have lost all their amps. your load test will tell you.

 

The battery test tool didn't show up from this local web shop that i will never use again....
Took a chance on a new battery that came with 4 years warranty, didn't have much time to drive the car. But went out today and it died a couple of hundred meters from the garage...first anti spin issues and then the engine died. Pretty scary consequence of some kind of electrical issue...

i have had anti spin messages in the dash before that killed the car in the driveway, then restarting and has been fine for weeks after......
Today i restarted the car and drove home again.

seems i have several issues, battery was one of them.
Im thinking wheel sensor and or throttle body issues.

I have an code reader and found several codes:
P1229 "throttle control circuit malfunction."
U1041 "SCP vehicle speed signal - invalid or missing data."
B1595 "Ignition switch - illegal input code." ( this might be old from when putting the key in and out several times rapidly to se if the little hatch inside worked or not, while looking around for power draws)
B2368 "Column adjust switch, out of range" (going to ignore this one for now :-) )
U1135 "Ignition status not obtained"
P0100 "Mass or volume air flow circuit. /Mass air flow sensor."
P220e2 "the fault code is not found in the database"


What do you guys think?

 

Found this great thread about P1229
https://www.jaguarforums.com/forum/x...-178564/page2/

 

When giving this some more thought, car was fine before accept giving stability control warnings sometimes..

Battery has been bad and created all sorts off issues and codes. ECU now has to re-adapt? when thinking about the stability control warnings, they showed up mostly when turning the wheels (cable issue), like in the parking lot or in sharp bends. The other day it was when driving slowly into a roundabout.

So basically what im thinking is that while the ECU is re-adapting and setting idling etc, one of the front wheel sensors give the wrong information, and anti spin is cutting throttle, while ECU is in some sort of re adaption phase, the level of throttle wasn't enough to handle the power cut off from the anti spin so the engine died. Even thou the ECU is responsible for handling the anti-spin i guess (?).

Maybe im totally wrong but this is going to be my approach

Im going to reset all codes, troubleshoot the sensors to see if they are all ok or not, clean all sensors and connections for TB, ABS, ECU etc, then give it another try.

 

ALL the wheels/tires should be the same size. Some people put larger on the rear?

Most of the time I had faults like this was when some dingbat put the rear wheels on the front and the fronts on the back!!!!!!!!!!

The rear wheels can NOT rotate faster than the front without the 'traction control' intervening.(unless you hit the disable switch)

The larger wheels/tires are fitted to the REAR!!!!!!

Could also be a front 'link-harness' issue for the speed sensors.

 

I have the same tire size all around
will have a extra look on the sensor cables and connectors, and that the cable isnt tight/over streched

 

As the very basic thing, did you check/clean/retighten all connections of the battery cables including those in the master fuse box in the boot and the connections at the false bulkhead and at the fuse boxes?

 

Thanks! The car is really clean and "fresh"....or how to say it... but will look into that as well. Got my hand on some electric cleaner spray and also some petroleum jelly/Vaseline spray to seal the connectors with after cleaning..

 

Progress is slow, i got the wrong diagram with me to the car, anyone have a diagram and pin point test for the Throttle body for AJ27 XJR? The ECU looks totally different from the aj26 version
Also looking for where the wheel sensors are connected, are they connected to the box attached to the ABS unit? There is only one big connector there, are all the sensors connectors attached to a bigger connector that in turn is connected to the ABS module?
If im having problems with the wheel sensors, will disabling traction control take them out of play completely, to verify that the problems go away when they are disabled?

 

Gus will have ALL electrical guides on his site.

jagrepair.com

 

The front wheel cables can break internally due to flexing.