Codes set

1991 FORD E-SERIES VAN
20 MILES • 6 CYL • 2WD • AUTOMATIC
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RUSTFARMER
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enter your question...91 with 4.9 gives code 54, but IAT tests good and 4.5 volts is being supplied and connection seems good. Code 81 also set.How to diagnose?
Jun 13, 2011 at 6:18 PM
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WRENCHTECH
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Use a scan tool when truck is cold and compare IAT temp to CTS temp. They should match.
Jun 13, 2011 at 7:24 PM
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RUSTFARMER
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My scan tool will not give actual temp readings from sensors, and I was under the impression that OBD1 systems don't do this. I have checked the resistance of these two sensors and they are very close to a match. I believe that code 54 for this system means the IAT circuit is open or reading -40 degrees F,however the coolant temp sensor is not setting a code. How can I tell if the IAT is actually sending a return signal to the ECM?
Jun 13, 2011 at 8:58 PM
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WRENCHTECH
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I already told you that. A real scan tool will give temps.
Jun 13, 2011 at 9:32 PM
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RUSTFARMER
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Perhaps you could suggest a "real scan tool" for OBD1 systems.
Jun 13, 2011 at 11:26 PM
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WRENCHTECH
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Snapon Solus or Modis, OTC Genisis or Pegasis, Launch X431
Jun 13, 2011 at 11:29 PM
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RUSTFARMER
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Thank you very much.
Jun 13, 2011 at 11:48 PM