Obtaining Fault Codes

Ensure ignition is off. Attach DRB-II to engine diagnostic connector. Connector is located on left side of engine compartment, near SBEC-II. See Fig 1. Start engine (if possible). Turn A/C switch on, then off (if equipped).
Turn engine off. Without starting engine, turn ignition on and access READ FAULTS function of DRB-II FUEL/IGN MENU. See DRB-II DIAGNOSTIC MODE under DIAGNOSIS WITH DRB-II & JEEP ADAPTER if necessary.
Record all fault messages displayed by DRB-II, and observe CHECK ENGINE light on instrument cluster. CHECK ENGINE light should come on for 3 seconds and then go out (bulb check).

Fig 1: Locating Diagnostic Connector

Courtesy of CHRYSLER MOTORS.

Fig 2: ECU Connector Terminal Identification

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Fig 3: 4.0L PFI Diagnostic Connector D1 & D2 Terminal Identification

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Fig 4: 4.0L PFI ECU Connector Terminal Identification

Courtesy of CHRYSLER MOTORS.