GM Service Manual Online
For 1990-2009 cars only

Perform the following checks:

    â€¢ Battery--Battery Inspection/Test. Refer to Battery Inspection/Test.
    â€¢ Wiring--Inspect the wiring for damage. Inspect all connections to the starter motor, solenoid, battery, and all ground connections. Refer to Circuit Testing , Wiring Repairs , Testing for Intermittent Conditions and Poor Connections and Connector Repairs.
    â€¢ Engine--Make sure the engine is not seized. Refer to Symptoms - Engine Mechanical.

If the battery, the wiring and the engine are functioning properly and the engine continues to crank slowly, replace the starter motor. Refer to Starter Motor Replacement.