Dandy. That leaves four possibilities and you already tried a new sensor, so we're down to three. The most likely causes are a spread terminal for the 5.0 volt feed wire or the signal wire. If the 5.0 volt terminal isn't making contact with the sensor's terminal you'll find 0.0 volts on the signal wire. If the signal wire terminal isn't making contact you will either find 0.0 volts or 5.0 volts on it. I only have Chrysler's method memorized but about 95 percent of other car brands work the same way. With a break anywhere in that signal wire circuit, including inside the sensor itself, the voltage in the computer could "float" to some random value due to the circuitry inside. The computer could try to run on that value. To prevent that they use a "pull-up" resistor tied to the 5.0 volt supply. It is so high in value that it has no affect on anything, that is, until that break in the signal circuit occurs. Then the resistor places 5.0 volts on that circuit which is what triggers the fault code.
If the break is in the signal wire going to the sensor, you will find the normal 0.5 to 4.5 volts, (approximately) at the sensor terminal but 5.0 volts at the computer, (and on a scanner). If it's the terminal that isn't making contact you will find 5.0 volts when you back-probe that terminal.
Since you found 0.0 volts on the signal terminal, if the sensor is good and the 5.0 volt feed terminal is making contact, that leaves your meter probe as the problem. After working on tvs and vcrs for over 40 years, I can tell you that even experts get fooled all the time with 0.0 volt readings. To double-check yours, measure on the terminal side of the connector where you can see for sure you're making good contact.
It is also possible they're using a "pull-down" resistor. That will put 0.0 volts on the signal wire when there's a break in that circuit.
Thursday, June 6th, 2013 AT 11:22 PM
