Diagnostic Aids
WARNING: This page is about a different car, the 2002 Pontiac Firebird and 2002 Chevrolet Camaro. However, it is still accessible from the selected car via links, so may be relevant.
- Test circuits 821 and 822 for electromagnetic interferences (EMI) induced by a wiring harness incorrectly routed too near the spark plug wires.
- Inspect for ABS DTCs. A faulty ABS condition may contribute to setting DTC P0503.