Map Sensor Question
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Map Sensor Question
86-f150,302 efi.....testing the map sensor...the reference voltage is fine at approx. 5 volts, but when I plug the connector back into the sensor, the voltage drops to 2.6 without even applying vacuum.
Sensor bad??? According to the manual, it isnt supposed to drop until I apply vacuum.
Sensor bad??? According to the manual, it isnt supposed to drop until I apply vacuum.
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Originally Posted by sainty333
86-f150,302 efi.....testing the map sensor...the reference voltage is fine at approx. 5 volts, but when I plug the connector back into the sensor, the voltage drops to 2.6 without even applying vacuum.
Sensor bad??? According to the manual, it isnt supposed to drop until I apply vacuum and then it is supposed to fall to 1 volt.
Sensor bad??? According to the manual, it isnt supposed to drop until I apply vacuum and then it is supposed to fall to 1 volt.
This was done during the KOEO test.
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From: Right Next to U
Ok...a little lesson on the Map Sensor. The 0.5v is the Reference Voltage. The ECC has a voltage regulator that steps the voltage down from the range of 10 to 14 volts dc. to a constant 0.5v. This is the voltage you had when you tested it. That is why its called a Reference Voltage. All the sensors will get this Reference Voltage....from the ECC.
The sensors will return the variable amount of this voltage to the EEC to show the status of the sensor system. What is this called...? Reference Voltage.
As the sensor ages and gets old (not everything lasts forever...even us humans are not mortals) the computer senses the difference when the sensor was new, and then compensates for the differences in the sensors values...As the sensor ages and it’s readings get worse a fault code will be stored in the KAM memory. If you get a code that the sensor is bad..replace it, reboot (min 30 min) drive it for 10 miles and get the next one fixed. Don't fix it if its not broken....
The sensors will return the variable amount of this voltage to the EEC to show the status of the sensor system. What is this called...? Reference Voltage.
As the sensor ages and gets old (not everything lasts forever...even us humans are not mortals) the computer senses the difference when the sensor was new, and then compensates for the differences in the sensors values...As the sensor ages and it’s readings get worse a fault code will be stored in the KAM memory. If you get a code that the sensor is bad..replace it, reboot (min 30 min) drive it for 10 miles and get the next one fixed. Don't fix it if its not broken....
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