Diagnostic Aids

If the engine has been allowed to cool to an ambient temperature (overnight), coolant and MAT temperatures may be checked with the "SCAN" tester and should read close to each other. A Code 25 will result if circuit No. 472 is shorted to ground.

Fig 1: Code 25: MAT Sensor Temp To High Flow Chart

Fig 2: Code 25: MAT Sensor Temp To High Flow Chart

Fig 3: Code 25: MAT Sensor Temp To High Schematic