Check Engine Light, Code 28?

93tealstang said:

My check engine light has recently started coming on and off. It starts usually as soon as the motor has reached full operating tempurature. I self checked for codes and came up with a code 28 which is "Vane Air Tempurature (VAT) sensor signal out of Self-Test Specification." Anyone know anything about this or where the sensor is located? Thanks for any help.

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There is no VAT on Mustangs, only on Mazda or MECS computer control systems. All the Mustangs use ECC-IV for the computer control system.

On MECS systems, the VAT performs the same function as the MAF does on ECC-IV systems.

The closest code to 28 (MECS) is 27 or 29 (ECC-IV). Here's the tech note for code 29...

Code 29 - Vehicle Speed Sensor (VSS) is an electronic sender mounted on the speedo pickup gear on the trans. It works the cruse control for both 5 speed and auto trans cars. On auto trans cars, it tells the computer to speed up the idle slightly as you slow down to a stop to keep the engine from stalling. Check to see if the electrical connector is plugged into it. Cost is under $30 and it is easy to replace.

Code 27 is the same sensor, slightly different problem symptoms.