System Diagnosis: Notes

NOTE: Self-diagnostic tests are written specifically for Chrysler's Diagnostic Readout Box (DRB). A generic scan tool may not be capable of performing all necessary test functions. Malfunction indicator (CHECK ENGINE) light can be used, but has limited diagnostic capability.

The self-diagnostic capabilities of this system, if properly used, can simplify testing. PCM monitors several different engine control system circuits.

If a problem is sensed with a monitored circuit, a DTC is stored in PCM, Malfunction Indicator Light (MIL) illuminates and PCM enters limp-in mode. In limp-in mode, PCM compensates for component failure by substituting information from other sources. This allows vehicle operation until repairs can be made.

Once DTCs are known, to determine the questionable circuit refer to CHARGING SYSTEM DTCS table under ENTERING ON-BOARD DIAGNOSTICS.

Perform circuit tests to repair or replace components as required. If problem is repaired or ceases to exist, the PCM will cancel that DTC after 50 ignition on/off cycles. To clear codes, refer to CLEARING DTCS procedure under ENTERING ON-BOARD DIAGNOSTICS.

A specific DTC results from a particular system failure. Components in that system are not necessarily the reason for that failure. The DTC does not condemn a specific component, it indicates a circuit malfunction.