ISC-E System Description

ISC-E System Description

The purpose of the Idle Speed Control-Electronic (ISC-E) System used on the 2.0L Ranger is to control engine rpm only by means of a DC motor throttle actuator. It does not control any other engine function such as air/fuel ratio, spark advance, exhaust gas recirculation, etc.

NOTE: The 1988 model year 2.0L Ranger uses an Aisan model Y 2V carburetor and Aisan DC motor idle speed control unit.

How To Use The Diagnostic Procedure

DESCRIPTION






NOTE: Use this procedure only when the idle speed is too high, too low or erratic.

The Idle Speed Control-Electronic (ISC-E) System has the capability to diagnose a malfunction within its own system. It advises the technician where to look for ISC-E problems through the use of a Self-Test computer program built into the ISC-E module. When triggered, the Self- Test simulates a variety of engine operating conditions, so that. operating conditions can be detected.

A response to the initiated Self-Test is reported to the technician as a pulsing series of voltage outputs that will appear on one of two testing devices: an Analog Voltmeter or Self- Test Automatic Readout (STAR) tester, Rotunda model 007-00017.

The series of voltage pulses are called a Service Code, representing a two-digit number. It is the two-digit Service Code that advises the technician of the nature of the ISC-E problem. Hooking up the Analog Voltmeter or STAR tester to the ISC-E System will be described and shown later.

After performing the "Self-Test", the technician must follow all diagnostic procedures in the Engine/Emissions Diagnosis Manual prior to replacing any components. This will help ensure service reliability.

NOTE: The ISC-E System uses only an Engine Running Quick Test, (No Key-On, Engine Off Quick Test)