p0108

I have a 98 grand prix se 3.1 and just recently had the problem of radiator fluid in the oil, so i bought a full gasket kit and had a friend put it on for me.I have the car back now the gaskets have all been replaced and there is no more antifreeze in the oil but now it is throwing a p0108 code and i need to get it inspected but it won't pass with the engine light on.Can anyone tell me what causes this code and what i can do to fix it . vaccum leak faulty map or what any help would be appreciated thanks

Welcome to AF.

The DTC indicates a problem with the MAP sensor (high input). Have your friend double check the work and make sure the MAP sensor is installed properly. Located behind the upper intake manifold about mid center towards firewall. Check vacuum lines to the intake manifold, sensor and the sensor electrical connector. Common problem after doing a gasket job on a 3100 engine. If all that is good maybe the MAP sensor went bad.

Thanks for replying to my question but could you tell me the name of the sensors and which connectors. Thanx again for your help

The sensor is the MAP - Manifold Absolute Pressure. See pic below. Connector is right on it.

http://i5.photobucket.com/albums/y186/lizzywiz/map.jpg

Does the pcv valve have anything to do with p0108 code.I notice when I crank the car up it sounds rough but quickly smoothes out. When does the computer check the map sensor 2 engine cycles or 3 and is there any test procedures in the tips and maintenance forum again thanks for the help.

No, sorry. The DTC is covered thoroughly in the GM FSM so we do not post anything at Tips & Maintenance as a result. However, you can search for older threads where someone else had a similar issue and what the solution was, if any.

The PCM module - computer checks the MAP signal once the engine has been running for a length of time that is determined by the startup engine coolant temperature and throttle angle. Technically you could say every drive cycle. The time ranges from 2 minutes at less than -22 degrees F or to 1 second at more than + 86 degrees F.

A bad PCV or any vacuum leak at the intake manifold area could cause the issue if it is affecting engine vacuum. So the first step is to make sure engine vacuum is good. Next check the PCM 5 volt reference signal at MAP input and then the output. MAP output signal varies from .1 volt low to 4 volts high. The MAP sensor responds to changes in intake manifold pressure which gives an indication of engine load.

I did an inspection of all the vacuum lines and they all looked fine,no cracks or breaks. I also looked at the condition of the engine oil and where you put oil into the engine it is very clean but where the pcv valve goes is very milky sludge. Could this be what is causing the p0108 code? Also the wire connector to the map sensor is missing the locking tab. Again I appreciate all your help BNaylor

Try the tap test on the map sensor yet?

Start it up, and at idle smack the map sensor firmly, but not to break it, with the handle of a screwdriver. If the idle changes as your tapping, or the car starts to run bad, you found your problem.....

Have you checked for proper B+ and ground on the MAP connector?

I have a GM MAP sensor in my toolbox I snagged from a car at the shop that was on its way to the junkyard. I think it might be from an older 3.1, but if the part number is the same, I'll just ship it to you free. (no guarentees its any good either)

There are a few numbers on mine, not sure what on is the p/n.

They are.....
466 (on top)
039 6327 (on top of where connecter goes in)
44 17406 (on bottom)

Do these numbers match up to yours?

Yes TBlake the # on mine is 466 too. Can you e-mail me at [email protected] and I will give you the address to mail it. thanks in advance

email sent!