Put the ODB 1 code reader on my stang today.


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Mar 5, 2023
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I went out the storage place and dug the ODB1 reader out of my old 1999 RV.

Hooked it up to my 1995 GT I just bought a couple of weeks ago.

For Key On Engine Off I get:
564 - Fan Control (FC) circuit failure – A/C and Fan Circuits
334 - EVP sensor is/was high – EVR (code reader book book says EGR closed valve voltage high)

When I ran this test the electric fan came on and did various speed tests (the fan would speed up during testing).

For Key On Engine Running, I get:
314 - AIR inoperative, Left or Front HO2S – Air Injection
311 - AIR system not working – Single, Right or Rear HO2S – Air Injection
632 - E4OD – Transmission Control Switch (TCS) should be cycled once between engine ID and Goose test

This car has an aftermarket exhaust, which is probably why I'm getting AIR (Thermactor) errors.
The TCS switch worked a couple of times I tried it, but then stopped working. I'm guessing the switch is bad.

Question: Why isn't my Check Engine Light coming on for these problems? The light works - I can gets by turning the key to the On position with the engine off (check all idiot lights this way).

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