The theft alarm module on the 9-5 is equipped with its own power source, so it can operate even when the main battery is disconnected. It uses two Sanyo CR17335 3V Lithium batteries, which get recharged while the car is running. However, the batteries lose their capacity with age, and the current eventually drops below a certain value, which triggers a warning in the self-diagnostic system.

If the batteries need replacement, you will start getting the following message on the SID every once in a while:  SERVICE THEFT ALARM 

Saab does not sell replacement batteries, you can only order a complete new module, which is a waste of money. Fortunately, you can find the batteries from an electronics supplier and replace them yourself, if you're handy with a soldering iron. The batteries need to be of the exactly the same type and model as the originals.

Do NOT solder the batteries directly! The direct contact with a soldering iron might heat the battery up too much and cause it to explode. Instead, make sure that the batteries you buy come with external leads attached to them.

Tools:

• 17 mm socket: wheel bolts;
• 10 mm socket: alarm module nuts, bumper lip screw;
• 8 mm socket: wheel lining screws;
• Torx T25 socket: wheel lining screws;
• torque wrench;
• car jack and axle stands;
• soldering iron;
• Phillips screwdriver.