2002 Pontiac Firebird Owner's Manual - Page 144

Voltmeter You can read the battery voltage on your voltmeter. If it reads less than 11 volts or more than 16 volts while your engine is running, and it stays there, you may have a problem with the electrical charging system. If you must drive a short distance with the voltmeter reading in a warning zone, turn off all your accessories, including your air conditioning and audio system. Brake System Warning Light Your vehicle's hydraulic brake system is divided into two parts. If one part isn't working, the other part can still work and stop you. For good braking, though, you need both parts working well. If the warning light comes on, there is a brake problem. Have your brake system inspected right away. Have it checked right away. Driving with the voltmeter reading in a warning zone could drain your battery. If you idle your engine for a while, the voltmeter reading might move into the low voltage zone (indicated by red dots). If the reading stays in the low voltage zone while you are driving, you may have a problem with the electrical charging system. Have it checked. While the voltmeter reads in the low voltage zone, your battery may not be able to power certain electrical accessories, like ABS. (If this happens, the ABS INOP light will come on. See "Anti-Lock Brake System Warning Light" in the Index.) United States Canada This light should come on briefly when you turn the ignition key to RUN. If it doesn't come on then, have it fixed so it will be ready to warn you if there's a problem. 2-88