Every Oldsmobile Alero has three main computers. The main engine computer controls all of the electronic components of the car. Resetting this computer resets the "Check Engine" light. The oil diagnostic computer runs the sensors that check the oil level and oil flow through the engine. Resetting this computer resets the "Low Oil Level" light. The security computer controls the factory security system. When the security light is on or flashing, your Alero won't start. Resetting this computer should allow you to start your Alero.
Open the bonnet of your Alero and secure it with the security bar. Make sure that the key is out of the ignition.
Disconnect the negative battery cable. To do this, you need to release the clamp that is on the battery post by using an adjustable wrench or pliers to loosen the clamp screw. The negative battery cable is the black cable.
Wrap a clean towel around the metal clamp on the end of the negative battery cable. Leave the negative battery cable unhooked for at least ten minutes. You can set the cable down as long as the towel is wrapped around it.
Replace the negative battery cable. Tighten the clamp screw until it is secure.
Start the Alero. You will have to reset the clock and the radio. Allow the car to idle for five minutes. If the check engine light comes on during this time, you need to have your Alero serviced.
Check the oil level in your Alero to make sure that the oil level is sufficient before you reset the oil diagnostic computer. To do this, you need to remove the oil dipstick in front of the engine. It has a black handle. Wipe off the dipstick with a clean paper towel. Replace the dipstick and remove it again. Look at where the oil stops on the dipstick. If it is in the acceptable range between the 'MAX' and 'MIN' marks, continue with the reset. If it is too low, you should add oil to see if that corrects the problem. If it is above the 'MAX' mark, you will have to drain some oil out.
Turn the key in the ignition to the 'On' position. This is the middle position where the radio will come on but the car stays off.
Leave the key in this position for ten minutes. If you are worried about draining the battery, turn off the radio and all of the lights.
Pump the accelerator three times while the key is still in the 'On' position. The pedal should go as far down as possible and then released fully before you pump it again.
Turn the key to the 'Off' position. Leave it off for one minute.
Start the ignition. The oil light should be off.
Turn the key in the ignition to start the Alero. If it won't start, leave the key in the 'On' position for ten minutes. All of the doors have to be closed when you do this.
Try to start the ignition again. Let it idle for five minutes before you put it in gear.
Take your Alero to a dealership as soon as possible to have the security codes reset. In most cases, doing this will prevent the security alert that stops the car from starting.
Even if resetting the appropriate computer gets the warning light to turn off, you should still take your vehicle in to have diagnostic tests done by a certified mechanic.