My car came up with a strange problem in which the check engine light came on and gave a code 3, which is a map sensor electrical problem. Car would start badly and not run very well. Well, the tech found a corroded wire running from the map sensor to the ecu harness plugs. That was fixed and the problem went away, bringing the engine back to normal operating conditions. The only problem i encounter now is a "check engine" light and still a code 3, with no engine problems whatsoever. Just in case, we tried three different known working ecu's and got the same results. The map sensor was also replaced and put into another vehicle to check its integrity and came out to be working fine.

What could be wrong now? Has anyone encountered such a situation before?

TIA

Mark


[Modified by se93, 8:25 AM 10/6/2002]

 

Manifold Absolute Pressure Signal
* Open or short in MAP sensor circuit
* MAP sensor
* ECM

 

Yes, i am aware of the map sensor code 3, but the entire harness was verified and all three map sensor wires leading to the ecu plugs were checked entirely. The corroded wire was completely replaced from the pin on the ecu plugs all the way to the map sensor. Why throw a code when the car functions perfectly? As i said before, three known perfectly working ecu's were installed and still the same problem. Also, the map sensor was replaced with a known working map sensor as well. This has been done on several occasions to make sure the map sensor hasn't gone bad.

Mark


[Modified by se93, 8:25 PM 10/5/2002]

 

reset the ecu

 

We have tried that about a million times. We have checked just about the entire vehicle without a clue to what could be causing this mysterious situation.

Mark

 

anyone?

 

ttt

 

how long after you reset it until it comes back on?

 

It will come on just about immediately. Reset the ecu, start up the car and bang, there goes the check engine light again. This is a really strange problem considering that the map sensor it has is a known working sensor and was tested on another vehicle. As mentioned previously, a corroded wire from the map sensor to the ecu plugs was the only problem discovered. After this was corrected, the car starts and functions as normal. I am worried though that there still might be something bad. What is it, well i have no idea.

Mark