Appendix:Self-Test Description

14-26 EEC-IV - Quick Test - All Engines
1989

APPENDIX: Self-Test Description


The Self-Test is divided into three specialized tests: Key On Engine Off Self-Test, Engine Running Self-Test, and Continuous Self-Test. 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 EEC-IV system by testing its memory integrity and processing capability, and verifies that various sensors and actuators are connected and operating properly.

The Key On Engine Off and Engine Running Self-Tests are functional tests which only detect faults present at the time of the Self-Test. Continuous Self-Test is an ongoing test that stores fault information for retrieval at a later time.

KEY ON ENGINE OFF SELF-TEST

At this time, a test of the EEC-IV system is conducted with power applied and engine at rest.

For Self-Test to detect errors in the Key On Engine Off Self-Test mode, the fault must be present at the time of testing. For intermittents, refer to Continuous Memory Codes.

SEPARATOR PULSE

A single 1/2 second separator pulse is issued 6-9 seconds after the last Key On Engine Off Test code. Then, 6-9 seconds after the single 1/2 second separator pulse, the Continuous Memory Codes will be issued.

CONTINUOUS MEMORY CODES

Continuous Memory Codes are issued as a result of information stored during continuous SelfTest, while the vehicle was in normal operation. These codes are displayed only during Key On Engine Off testing and after the separator code. These codes should be used for diagnosis only when Key On Engine Off and Engine Running Self-Tests result in code 11 and all Quick Test Steps 1.0 through 5.0 have been successfully completed.

NOTE: The separator code and Continuous Memory Codes follow Key On Engine Testing codes ONLY.

ENGINE RUNNING SELF-TEST

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

ENGINE IDENTIFICATION CODES (ID CODES)

Engine ID codes are issued at the beginning of the Engine Running Self-Test and are onedigit numbers represented by the number of pulses sent out. For gasoline engines, the engine ID code is equal to one-half the number of engine cylinders (i.e. 2 pulses = 4 cylinders). For the 7.3L Diesel engine, the ID code = 5. These codes are used to verify the proper processor is installed and that the Self-Test has been entered.

DYNAMIC RESPONSE CHECK

The dynamic response check verifies the movement of the TP, VAF, and MAP sensors during the brief Wide-Open Throttle (WOT) performed during the Engine Running Self-Test. The signal for the operator to perform the brief WOT is a single pulse or 10 code on the STAR Tester.