Codes set

Tiny
RUSTFARMER
  • MEMBER
  • 1991 FORD E-SERIES VAN
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 20 MILES
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?
Monday, June 13th, 2011 AT 6:18 PM

6 Replies

Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
Use a scan tool when truck is cold and compare IAT temp to CTS temp. They should match.
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Monday, June 13th, 2011 AT 7:24 PM
Tiny
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?
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Monday, June 13th, 2011 AT 8:58 PM
Tiny
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I already told you that. A real scan tool will give temps.
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Monday, June 13th, 2011 AT 9:32 PM
Tiny
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Perhaps you could suggest a "real scan tool" for OBD1 systems.
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Monday, June 13th, 2011 AT 11:26 PM
Tiny
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Snapon Solus or Modis, OTC Genisis or Pegasis, Launch X431
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Monday, June 13th, 2011 AT 11:29 PM
Tiny
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Thank you very much.
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Monday, June 13th, 2011 AT 11:48 PM

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