Introduction

DEFINING INTERMITTENT DRIVEABILITY SYMPTOMS

The Rotunda EEC-IV Monitor (007-0047F) and the Rotunda EEC-IV Monitor Recorder (007-00021) are useful tools for diagnosing intermittent driveability symptoms which are unable to be resolved through the diagnostics in Pinpoint Tests.

By definition, an "intermittent" symptom is a randomly occurring drive symptom from which no diagnostic codes are reported to the Rotunda Super Star II tester (007-0041B) or other diagnostic equipment. Often the Quick Test results in a pass, while the symptom remains.

Before proceding with the following procedures, be sure that:

- Customary mechanical system tests and inspections reveal no obvious problems.

REMEMBER: Mechanical component problems can make a good Electronic Engine Control (EEC) system react abnormally.

- EEC Quick Test and related Pinpoint test diagnostics have been successfully completed, and the symptom is still occurring after all recommended procedures have been performed.

- Review of the Technical Service Bulletins (TSBs) reveals no applicable article. (If applicable articles are found, perform the actions in the article prior to proceeding with tests).

PURPOSE

The Rotunda EEC-IV Monitor (007-0047F) functions as a "window" into the EEC system. Through this "window" the user is able to view the same sensor and actuator values the Powertrain Control Module (PCM) uses to make decisions about engine performance. The EEC-IV Monitor displays these values for both static (Key Off Engine Off) and dynamic conditions (Key On Engine Running). The advantage of the Rotunda EEC-IV Monitor Recorder (007-00021) is the ability to take a "snapshot" of selected PCM signals that can be stored and reviewed later.

The diagnostic procedures used in the EEC Intermittent Fault Diagnosis is a symptom based approach for isolating the faulty system, circuit, or component. In such cases, the use of a monitor will enhance the ability to eliminate possible EEC system faults and help locate mechanical faults.

NOTE: It is important to perform EEC Quick Test before proceeding. Diagnostic trouble codes must be recorded before disconnecting the PCM harness to install the Monitor, as codes will be lost when the PCM is disconnected.