engine code p0107????????

[vegasviper]

Map/baro circuit low input. I replaced pcm, wiring harness, map sensor and code3 still on. What can it be, what else can i do????????

Thanks

 

[Viper Specialty]

Just taking a stab here, but from my experience, a LOW input means a short somewhere, as a high input occurs when the sensor is unplugged.

Which harness did you replace? the ACTUAL front wiring, (including the Fuse Box & PCM plugs) or the engine side of the harness?

Also, it could very well be your VEC-2, as the VEC-1 & 2 alter the MAP signal.

May be worth your while to get a manual if you dont have one, get a continuity tester, and pull the FAR LEFT PCM plug, and check continuity of the wiring from the PCM plug to the sensor connector. (the pin output w/wire colors is in the "connector pinout" section, 8W-80-40).

EDIT- had a couple extra minutes. On C1 PCM plug, (far left), the DG/RD wire is Pin-27, the BK/LB wire is Pin-4, and the OR wire is Pin-17. Check continuity from those pins to the MAP sensor connector.

Lastly, I am not positive how the VEC-2 connects, but if it connects IN SERIES with the DG/RD wire like the VEC-1 did, you have to take a sewing needle, and push it into the insulation on the HARNESS side of the wiring, and check continiuity from that rather than the Pin, as the VEC systems will block a continuity tester, so you have to bypass. may want to check continuity over the VEC connections as well...they could be your problem too.

 

[1TONY1]

Which car ? If the Roe car..... What wiring harness did you replace ? I would disconnect the four Vec2 connectors and connect the factory connectors back together. This will take the Vec2 and Vec2 harness out of line and eliminate it (or not) from being the problem. Go ahead and remove power from the vec2 while the harness is disconnected just to be on the safe side. You could take away the positive or the negative, whichever is easier. You can drive it without the Vec2....just don't get into boost.

 

[vegasviper]

Its the Roe car. I replaced the harness that includess the fuse box

 

[vegasviper]

So, a bad Vec2 could cause this problem??????????

 

[Sean Roe]

Hi Steve,
The VEC2 is not connected in any way to the MAP sensor circuit by common connector, vacuum connection or any other form of wiring (unlike the VEC1).
If it's related to the Supercharger, the only thing I've seen that can cause it to set is if the bypass valve is not working correctly (balancing the manifold pressure). With the engine idling, the valve should be open. There's a short rod that connects the vacuum diaphragm to the butterfly valve. You should see it move open to closed as you rev the engine. If it does, it's good. If it doesn't, it may have a vacuum leak to the diaphragm.
Otherwise, I've personally experienced many phantom MAP sensor codes over the years. This is on cars with no VEC1, VEC2, Supercharger or anything else other than the stock manifold and PCM (changing PCM's and MAP sensors usually doesn't help). I really have no explanation for why sometimes a Viper can get into this constant "setting the code mode", which later goes away without ever really finding any actual cause. The only conclusion I have is that it must be a poor connection somewhere in the system, as we know the electrical connectors on these cars are not very good.

Regards,
Sean

 

[Ulysses]

Phantom codes happen all the time, the triggering event being an anamolous spike. That's why some codes require several drive cycles before they set the mil, but are stored in memory in the wait state. Sometimes, a few drive cycles aren't enough. If it doesn't come back, then there is nothing to worry about.

 

[vegasviper]

Sean, the Bypass valve does not seem to be opening and closing when reving the engine as mentioned.

 

[Sean Roe]

Sean, the Bypass valve does not seem to be opening and closing when reving the engine as mentioned.

Ok, read #14 on your troubleshooting guide (MAP sensor code) and call for a replacement part once you determine where the vacuum leak is (at the hose connection, T fitting or the vacuum diaphragm).

Regards,
Sean