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Old 11-11-2010, 09:23 PM
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Blue Bowtie Blue Bowtie is offline
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Re: 94 Roadmaster ALDL A/B jumper runs fan

Both conditions are correct. The 1994 and 95 B- and D-Bodies require a scanner to access stored codes. The old method of jumpering the ALDL to force the MIL to strobe out the stored codes is not applicable. My '94 Impala acts exactly the same way.

Also, even with the older ECMs, once in diagnostic mode (ALDL jumpered) the electric cooling fan will operate. That is normal all the way back to my 1986 Trans Am, and probably some even older ECMs with the 8K PROMs and no CALPAK.

Further, many places which offer free code scanning (like Auto Zone and other chains) will be unable to scan your vehicle since it is not truly OBD-II. A Tech II, Snap On MT2500, and some Actron scanners will be able to access the ECM. Some PC software programs with a proper adapter can also access the ECM data.
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