Jaguar 1998 XJ8 radio won't turn on

Jump Start of Vehicle Battery


IF THE BATTERY YOU ARE USING TO JUMP-START THE VEHICLE HAS RECENTLY BEEN CHARGED IT MAY STILL BE GASSING, COVER THE VENT PLUGS OR COVERS WITH A DAMP CLOTH TO REDUCE THE RISK OF EXPLOSION SHOULD ARCING OCCUR WHEN CONNECTING THE JUMP LEADS.

Turn off all electrical ancillary circuits such as radio, lights, indicators etc. If the reason for a flat battery is unknown the condition may be as a result of an electrical short circuit, so care must be taken during the Jump-start process and subsequent to connection to ascertain if this is the case. A short circuit or un-isolated ancillary load can cause arcing when the jump leads are connected, a small 'crackle' is normal but any spark or flash is an indication of a problem that should be rectified before attempting to Jump-Start the vehicle.

Jaguar do not recommended that the vehicle is jump started, and If at all possible it is preferable to replace the flat battery with a suitable fully charged unit rather than jump-start the car. However if it is done it should be carried out by suitably qualified personel. Garage services and services like AA and RAC homestart should be used whenever possible.

Obviously there are occasions when carrying out this proceedure yourself is the only practical way proceed.

If there is no option but to jump-start the discharged battery should be removed and recharged immediately after jump starting to avoid permanent damage.

High quality, heavy duty Jump leads must be used as the current consumption during starting is very high, and a voltage loss will be
exhibited though the jump leads, increasing current requirement.

Make sure that the Jump Start battery is of the same voltage as the vehicle, and suitable to provide the required starting current.

MAKE SURE THAT THE ENDS OF THE JUMP LEADS DO NOT TOUCH EACH OTHER OR GROUND AGAINST THE VEHICLE BODY AT ANY TIME WHILE THE LEADS ARE ATTACHED TO THE BATTERY. ARCING AND VERY RAPID DISCHARGE CAN CAUSE THE BATTERY TO EXPLODE.

Connect the jump leads in the following sequence.
Connect Positive Jump Lead to Jump Start battery positive terminal.
Connect Positive Jump Lead to Vehicle battery positive terminal.
Connect Negative Jump Lead to Jump Start battery negative terminal.
Connect Negative Jump Lead to a suitable vehicle ground point at least, 300 mm (12 in) from the battery terminal e.g. engine lifting bracket, do not do not connect directly to the vehicle battery terminal.

Start the vehicle and rev to 2000 rpm, then allow tickover for 5-10 minutes.

Do not attempt continued repeated starting of the vehicle, this will cause heat build up at the terminals and though the jump leads degrading the leads performance and adding to voltage loss.

Allow 3-4 minutes recovery time for the leads and Jump Start battery between attempts to start.

Before disconnecting the jump leads, switch on the heated rear screen, to reduce the alternator voltage peak when the leads are removed, as this can damage electronic equipment.

Disconnect the jump leads in the reverse order to the connecting sequence taking great care not to short the ends of the leads.

Do not rely on the alternator to restore a discharged battery.
Ensure that the battery is recharged or replaced with a fully recharged unit
as soon as possible.

Following Jump-starting of a compleately discharged battery, you may need to carry out a Green ECM drive Cycle, this will allow the powertrain control module to 're-learn' idle values, and most likely need to re-enter your radio code, details of these can be found at. http://www.bluejag.co.uk