Codes for 1988 Mercury Cougar

Tiny
DISCENNA57
  • MEMBER
  • 1988 MERCURY COUGAR
  • 2WD
  • AUTOMATIC
  • 85,556 MILES
Hi I was wondering if anyone can tell me what these codes mean and what I should do to fix the problem?

Code 12 - Cannot control RPM during self check or Idle speed control problem

Code 21 - Coolant temp out of range

Code 51 - Coolant temp sensor voltage too high or open circuit

Thanks!
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Sunday, February 20th, 2011 AT 12:52 AM

3 Replies

Tiny
RASMATAZ
  • MEMBER
Try replacing the engine coolant temperature sensor and go from there-
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Sunday, February 20th, 2011 AT 12:56 AM
Tiny
DISCENNA57
  • MEMBER
Ok thats what I was thinking but I did replace both the sensor and sender about a year ago. I dont know if that helps with anything, but my car has been very hard to start and its having trouble idling.

Thanks alot for your help.
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Sunday, February 20th, 2011 AT 8:48 PM
Tiny
RASMATAZ
  • MEMBER
Recommend you check fuel pressure with a fuel pressure gauge if its within specs-could be leaking down
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Sunday, February 20th, 2011 AT 10:42 PM

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