Test Description

Do not depart from the instructions provided here. Anyone who departs from the following instructions must first establish that he may compromise his personal safety and the vehicle integrity by his choice of methods, tools or parts.
The Integrated Vehicle Speed Control (IVSC) contains a self-test capability, consisting of a Key On, Engine Off (KOEO) and Key On, Engine Running (KOER) routine, which utilizes output error codes similar to EEC-IV subsystem ``Quick Tests.'' These ``Quick Tests'' then refer to Cruise Control/Testing and Inspection/Procedures/Pinpoint Test Charts for specific components diagnosis.
Testing for the IVSC is divided into two formats: the Quick Test and the Pinpoint Tests. The Quick Test is a functional IVSC system test. The Pinpoint Tests are specific component tests.
The Quick Test checks all IVSC components except the speed sensor, which must be checked separately. To test and service the IVSC system, perform the quick test first. If the system passes, check the speed sensor. If failure codes are generated, do only the Pinpoint Test specified by that particular failure code.
After all test and services have been completed, repeat the entire Quick Test to verify that the IVSC system operates properly.



For QUICK TESTS charts, refer to DIAGNOSTIC CHARTS.

The Quick Test is a functional test of the IVSC system consisting of basic Test Steps (described below). Otherwise, inaccurate diagnosis or the replacement of satisfactory components may result.

Quick Test Steps

1. Perform a visual check for obvious faults then properly prepare the vehicle for testing.
2. Ensure proper equipment is used for gathering test data is ready prior to testing.
3. Key On, Engine Off Self Test is a static check of IVSC inputs and outputs.
4. Key On, Engine Running Self-Test is a dynamic check of the engine in operation.

Visual Check & Vehicle Preparation

Correct test results for the Quick Test are dependent on the proper operation of related non-IVSC components systems. It may be necessary to correct faults in these areas before the IVSC will pass the Quick Test.
Before hooking up any equipment to diagnose the IVSC system, make the following checks:
1. Check all engine vacuum hoses for leaks or pinched hoses (servo to dump valve and servo to manifold vacuum).
2. Check IVSC and EEC system wiring harness electrical connections for proper connections, faulty connectors, corrosion and proper routing of harness. It may be necessary to disconnect or disassemble the connector assembly to perform some of the inspections.
3. Check EEC-IV and IVSC sensors and actuators for physical damage.
4. Perform all safety steps required to start and run operation vehicle tests.
5. Apply emergency brake. Place the shift lever in PARK (NEUTRAL for manual transmission).
6. Turn off all electrical loads.
7. Verify engine coolant is at specified level.
8. Start engine and idle until upper radiator hose is hot and pressurized and throttle is off fast idle.
9. Turn ignition key off.
10. Service items as required, then proceed to equipment hookup.

Quick Test Self-Test

Quick Test Self-Test is divided into two specialized tests: Key On, Engine Off, and Key On, Engine Running. The Self-Test is not a conclusive test by itself, but is used as a part of the functional Quick Test diagnostic procedure. The processor stores the Self-Test program in its permanent memory. When activated, it checks the IVSC system by testing its functional capability and verifies that various sensors and actuators are connected and operating properly.
The Key On, Engine Off and Engine Running tests are functional tests which only detect faults that are present at the time of the Self-Test.

Key On, Engine Off Test

At this time, a test of the IVSC system is conducted power applied and engine at rest. The fault must be present at the time of testing for errors to be detected in this test.

Key On, Engine Running Test

At this time, a test of the IVSC system is conducted with the engine running. The system is checked under actual operating conditions and at normal operating temperatures. The actuators are exercised and checked for corresponding results.

Service Codes

Fig. 34 Self-Test Output Code Format:

The EEC-IV system communicates service information by way of the Self-Test codes. These service codes are two digit numbers representing the results of the Self-Test.
The service codes are transmitted on the Self-Test output (found in the Self-Test connector) in the form of timed pulses, and read by the technician on a voltmeter or on the STAR tester, Fig. 34.

Fig. 35 Reading Codes With Analog Voltmeter:

Reading Codes-Analog Voltmeter

When a service code is reported on the analog voltmeter for a function test, it will represent itself as a pulsing or sweeping movement of the voltmeter's needle across the dial face of the voltmeter, Fig. 35. Therefore, a single-digit number of three will be reported by three needle pulses (sweeps). However as previously stated, a service code is represented by a two digit number, such as 2-3. As a result, the Self-Test service code of 2-3 will appear on the voltmeter as two needle pulses (sweeps), then, after a two second pause, the needle will pulse (sweep) three times.

Fig. 36 Reading Codes With Self-Test Automatic Readout (STAR) Tester:

Reading Codes, Self-Test Automatic Readout (STAR) Rotunda 007-00004, or STAR Rotunda 007-000717, or Equivalent

After hooking up the STAR tester and turning on its power switch, the tester will run a display check and the numerals 88 will flash in the display window, Fig. 36. A steady 00 will then appear to signify that the STAR tester is ready to start the Self-Test and receive the tests service codes.
To receive the service codes, press the push button at the front of the STAR tester. The button will latch down, and a colon will appear in the display window in the front of the 00 numerals. The colon must be displayed to receive the service codes.
If for any reason the technician wishes to clear the display window during the Self-Test, he must turn off the vehicle's engine, press the tester's push button once to unlatch it (colon will disappear), then press the button again to latch down the button (colon will appear again). Every time the STAR tester is turned off, the low battery indicator (LO BAT) should show briefly at the upper left corner to the tester's display window. If the LO BAT indicator shows steadily at any other time during the operation of the STAR tester with any service code, turn its power switch to OFF and replace the 9-volt battery in the tester.
The STAR tester will display the last service code received, even after it has been disconnected from the vehicle. It will hold the service code on the display until the power is turned off or the push button is unlatched and latched.