Electronic Instrument Cluster: Notes
AC and DC voltage measurements required in diagnosis of speed control on vehicles with an electronic instrument cluster require the use of a Beckman model 3020, Fluke model 8022A, or an equivalent voltmeter.
The speed signal is provided by the electronic speedometer rather than the speed sensor. DO NOT perform the speed sensor test on vehicles equipped with the electronic speedometer. Rather connect an AC voltage across the Circuit 150 DG/W and ground leads at the amplifier. See Fig 1 . With the wheels raised and the vehicle speed at 30 mph, the AC voltmeter should read approximately 6-24 volts.
Refer to ELECTRONIC INSTRUMENT CLUSTER SPEED DIAGNOSIS CHART (Test Steps K1 through K4).
The Integrated Vehicle Speed Control (IVSC) contains a self-test capability.
Key On, Engine Off (KOEO) and Key On, Engine Running (KOER) routines output error codes in a manner similar to EEC-IV subsystem "Quick Test", which then refer to Pinpoint Tests for specific component diagnosis.
The Rotunda Speed Control Automatic System Tester 007-00013 or equivalent cannot be used for IVSC diagnosis. The Rotunda Self-Test Automatic Readout (STAR) Tester 007-00017, Super STAR Tester 007-00019, or Analog volt-ohmmeter (VOM) 059-00010 or equivalent, 0-20 VDC (alternate to STAR) is required to perform the IVSC Quick Test and display error codes.
A Rotunda Breakout box 014-00322 or equivalent can also be used for convenience during Pinpoint Testing.
Testing for the IVSC is divided into two formats: the Quick Test and 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 tested 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, perform 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.