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Switch Tests

Fig. 8 DEFI diagnostic codes. 1984:




Fig. 9 DEFI diagnostic codes. 1985:





Refer to Figs. 8 and 9 for trouble code explanations.
When all stored trouble codes have been displayed for the third time, the ECM will automatically begin the ``Switch Tests.'' To perform these checks, proceed as follows:
1. Display of trouble Code .7.0 signals the beginning of the ``Switch Tests.'' This code will continue to be displayed until the proper test action is taken. When ready to begin tests, depress, and release service brake pedal. This begins the test sequence by displaying Code .7.1.
2. With Code .7.1 displayed, depress the service brake pedal again to test the brake light or cruise control circuit. When this check is completed, the test program will automatically sequence to Code .7.2. If the test action is not performed within 10 seconds, the test program will automatically sequence to ``.7.2'' and Code .7.1 will be stored in the ECM memory as ``Not Passed.''
3. With Code .7.2 displayed, depress the throttle from idle to wide open throttle and release. This action allows the ECM to analyze the operation of the throttle switch. When this check is completed, the test program will automatically sequence to Code .7.3. Again, if action is not taken within 10 seconds, a Code .7.2 will be stored as ``not passed.''
4. With Code .7.3 displayed, shift the transmission lever to Drive then to Neutral. When this check is completed, the test program will automatically sequence to Code .7.4. This action must be taken with in 10 seconds or a Code .7.3 will be set.
5. With Code .7.4 displayed, shift the transmission lever to Reverse, then to Park. Shift transmission within 10 seconds or a Code .7.4 will be set. When this check is completed, the test program will automatically sequence to Code .7.5. On models without cruise control, Codes .7.5, .7.6 and .7.7 will be displayed during the switch test. When these codes are displayed, allow each code to reach its 10 second time out limit. After the time out period has elapsed, the display will advance to the next code. After Codes .7.5, .7.6 and .7.7 have timed out, Code .7.8 will be displayed. Refer to step 9 and complete this step within 10 seconds or Code .7.8 will be set. Steps 6 through 8 apply only to models equipped with cruise control.
6. Perform step 5 as described above. When step 5 is completed, the test program will automatically sequence to Code .7.5. With Code .7.5 displayed, turn instrument panel cruise control switch from off to on, then back to off. When this check is completed, the test program will automatically sequence to Code .7.6. Perform this test within 10 seconds or code .7.5 will be set.
7. With Code .7.6 displayed, turn instrument panel cruise control switch to On position, then depress and release set/coast button. When this check is completed, the test program will automatically sequence to Code .7.7. If this test is not completed within 10 seconds, Code .7.6 will be set.
8. With Code .7.7 displayed, turn cruise control instrument panel switch to On position, then depress and release resume/acceleration switch. When this check is completed the test program will automatically sequence to Code .7.8. If this test is not completed within 10 seconds, Code .7.7 will be set.
9. With Code .7.8 displayed, depress the ``Average'' or ``Instant/Average'' button on the fuel data panel. When this check is completed, the test program will automatically sequence to Code .7.9. Again this must be done within 10 seconds or a Code .7.8 will be set.
10. With Code .7.9 displayed, depress the ``Reset'' button on the fuel data panel within 10 seconds to test the function of this switch. When this check is completed the test program will automatically sequence to Code .8.0. If this test is not completed within 10 seconds, Code .7.9 will be set.
11. With Code .8.0 displayed, depress and release ``Outside Temperature'' button twice. This check must be completed within 10 seconds or Code .8.0 will be set. It may be necessary to start engine and operate ECC system in Auto and 60 modes in order to close the contacts of the compressor cycling switch.
12. With the switch tests completed, the ECM will now go back and display the switch test code(s) which did not test properly. Each code which did not pass will be displayed beginning with the lowest number. This time through, the codes will not disappear until the tested component has been repaired and/or tested for proper operation.
13. Upon completion of the trouble code and switch test displays, the ECC panel will remain in the diagnostic mode and display ``.0.0'' and then ``.7.0'' until the ECC mode is selected or the ignition is turned Off.


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