GM Service Manual Online
For 1990-2009 cars only
    • For vehicles equipped with the 43.L engine, refer to Enhanced Ignition System Diagnosis in Engine Controls-4.3L.
    • For vehicles equipped with the 5.0/5.7L engine, refer to Enhanced Ignition System Diagnosis in Engine Controls-5.0/5.7L.
    • For vehicles equipped with the 7.4L engine, refer to Enhanced Ignition System Diagnosis in Engine Controls-7.4L.