Help: 88 Cadillac ECM output overrides

1988 Cadillac Sedan DeVille, 4.5L
Gentlemen,
I am trying to test my EGR valve using the on board diagnostic capability built into the digital dash. However, the ECM will not enter the "ECM Output
Override" mode. I can get to all other modes. Once in the "7.0 System Ready" mode and I can hit the "HI" button, and it will it advance to the "E.9.5" mode. However, at that point the "ECON" button will not advance to the "E.6.1" (VCC Solenoid) mode.
The "ECON" button works normally when using the air conditioning, and to get to other diagnostic modes.
Anyone have any idea why the computer is behaving this way.
TIA Bill
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R U proceeding this way?
Engine running>cruise instrument panel switch On>turn engine Off and within 2 seconds turn Ign On>enter diagnostics and display E.9.5>depress accelerator pedal(throttle switch Open) and release it(throttle switch Closed)>at that point the ECM output cycling mode begins. The output cycling mode will end automatically after 2 min of cycling and the display will switch from E.9.5 to E.9.6
Hope this helps some.....
Dave S(Texas)
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thanks. I will try it later tonight.
On Wed, 13 Oct 2004 17:08:50 -0500, snipped-for-privacy@webtv.net wrote:

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