Diagnostic Aids
WARNING: This page is about a different car, the 2007 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
IMPORTANT:
Be sure to verify that the ECM engine grounds are secure and clean.
If DTC P2520, P2521cannot be duplicated, reviewing the Failure Records vehicle millage since the diagnostic test last failed may help determine how often the condition that caused the DTC to set occurs. This may assist in diagnosing the condition.
If the condition is not present, refer to Testing for Intermittent Conditions and Poor Connections .