Self-Diagnostic System: Description: Notes

Self-diagnostic system is used for diagnosing malfunctions of Electronic Concentrated Control System (ECCS) sensors and actuators. Engine Control Module (ECM) has a number of available diagnostic modes within computer. Some models have On-Board Diagnostics (OBD-II) self-diagnostic capabilities.

Pickup has 5 diagnostic modes. Before selecting any mode of self-diagnostics, perform procedures in the BASIC TESTING - 2.4L article. Doing so prevents wasted time and false diagnostic results.