The 5 volt supply is the violet/white wire
the signal is dark green/red
and the ground circuit is black/light blue
the following is the test to perform when the map sensor voltage is too high as in yoru case.
1. Start engine, and backprobe connecter to find map sensor voltage. If voltage is more then 4.6 volts go to step 5 if its under 4.6 volts go to step 2.
2. Wiggle map sensor harness and see if voltage changes whilst wiggling the harness, if so repair the harness for a short or bad connector on map sensor. If wiggling does nothing go to step 3.
3. Check for a open in the map sensor signal, map sensor internal open, or a open ground in the map sensor circuit, or map sensor harness shorting to power.
4. Turn engien off and the igniiton off. Disconnect MAP sensor electrical connector and connect a jumper between sensor signal circuit and map sensor ground circuit at the map sensor connector. Try to start engine and read map sensor voltage should get no response, if you get no voltage then the map sensor signal circuit is shorted to the map sensor 5volt supply circuit.
5. If map sensor voltage is one volt or more go to next step, if less then one volt replace the map sensor.
6. Move jump wire from MAP to sensor to ground circuit to a good engien ground. Read map sensor voltage with engine running or cranking engine. If voltage is more then one volt go to next step. If less then one volt repair open map sensor ground circuit.
Turn ignition off and disconnect PCM connector. With the ohmmeter check resistance of the MAP sensor cignal circuit between Map sensor connector and PCM connector terminal no 36. If resistance is less then 5 ohms replace pcm if resistance is 5 ohms or more repair open map sensor signal circuit
in another note this is best performed with a scan tool to get the voltage as accurate as possible for testing.
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Wednesday, January 13th, 2010 AT 1:49 PM