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-   -   got a p0108 code (https://www.gmforum.com/1992-1999-91/got-p0108-code-254701/)

showshocka2k Mar 31, 2007 03:30 PM

got a p0108 code
 
got a p0108 code on my 97 sse. can somebody tell me where the PCV and the mass air flow sensor is? got pics to show also?

bill buttermore Mar 31, 2007 11:09 PM

According to Techinfo, P0108 for a '97 is Manifold Absolute Pressure (MAP) sensor circuit high voltage. The MAP sensor sits on top of the pcv valve housing on the passenger end of the UIM you just changed out. The Mass Air Flow (MAF) sensor sits on top of the throttle body on the other side of the engine.

Did you make sure you had an o-ring on the bottom end of the pcv valve when you installed it? Was there a spring for the top of the pcv valve? Was the big o-ring in place under the pcv chamber cover? Is the electrical connector for the MAP in tight? Is the seal installed on the MAP sensor and in good condition? Are the locking tabs properly engaged? It seems like these would affect the manifold pressure readings.

From Chilton's 28200:

1. Visually check the connector, making sure it is properly connected and that all of its terminals are straight, tight, and free of corrosion.

2. With the ignition ON, check the voltage between terminals A and B. It should be above 4 volts. Apply 15 inches of vacuum at the MAP vacuum port and check the voltage again. The voltage should be 2 volts now.

NOTE: When pumping up the vacuum and releasing the vacuum, check to make sure the voltage readings are smooth. When applying vacuum to the sensor, the change in voltage should happen instantly. A slow change in voltage could point to a faulty sensor.

3. If the sensor voltage is not within specification, check for a 5 volt reference at terminal C. If the reference signal is found, the sensor is faulty.

4. If the sensor and circuits are functional, the PCM may be faulty.

Going to solicit smarter person to check this advice for you....

showshocka2k Apr 1, 2007 12:07 AM


Originally Posted by bill buttermore
Did you make sure you had an o-ring on the bottom end of the pcv valve when you installed it? Was there a spring for the top of the pcv valve? Was the big o-ring in place under the pcv chamber cover? Is the electrical connector for the MAP in tight?

Is the seal installed on the MAP sensor and in good condition?
Are the locking tabs properly engaged?

Check!
Thanks bill. I checked everything and I noticed that my little MAP sensor piece is actually in 2 pieces. (like top and bottom) it looks as if the seal around the square shaped MAP sensor is broken and is unsealed which is making it two parts like a flat top part and a flat bottom part now that seem to have to be clicked together, then put into the clamps on the UIM. Is that right?
Can I just seal around the edges to make it right for now? Do you think that’s why my car is running rough at idle and feels like it’s missing at around a constant speed of 30mph? I also noticed that the car was having this problem before the UIM and LIM change so I feel relieved that it’s nothing I caused doing the change.

bill buttermore Apr 1, 2007 11:05 AM

You can certainly try to re-assemble it, seal it up and reattach it. If it runs well and doesn't set the code again, you're good.

willwren Apr 1, 2007 11:58 AM

Don't focus only on the MAP sensor. Pull out your PCV and check for the lower o-ring. It should be around the PCV valve just below the lip. The plastic clips that hold the MAP sensor are very brittle when they're old. You can use a couple zip-ties to hold the MAP sensor down firmly until you can get a new replacement PCV/MAP cap.

showshocka2k Apr 1, 2007 12:50 PM

Just took the PCV assembly. off and checked for the o-ring, it's there. sealed the 2 piece MAP sensor with RTV and the car is still shaky at idle and at a constant speed of about 20 to 35mph. got a guy I hooked up with at the local parts store that lets me purchase parts for half price. I think im going to try for a new MAP sensor, checked it out and I original price is 63 bucks, or do I need to check anything else first before buying?

bill buttermore Apr 1, 2007 06:16 PM

If you have the tools to use the procedure to check out your old one, you could see if it is truly the problem. Otherwise, I guess its a $30 roll of the dice. Was there a big o-ring in place to seal the pcv chamber/MAP cover?

Did you get a new pcv cover with the APN kit ?

showshocka2k Apr 1, 2007 10:36 PM

yes a big o-ring

bill buttermore Apr 1, 2007 11:33 PM

Well, that's about all you can check in the near vicinity of the pcv without checking the sensor itself. That, of course, is the best way to tell if you really need a new one. I suppose you could look for other large vacuum leaks like the hose to the brake booster on the back of the UIM and check all your vacuum hoses. But if the sensor was in pieces and you got a code for it, it seems a reasonable thing to replace it.

showshocka2k Apr 6, 2007 07:58 PM

5 Attachment(s)
Changed my MAP sensor today and still the same problem. The check engine light went out but the car stills runs rough and acts like it wants to shut down at idle even though it never shuts off...It's great when I’m at a stop and I pull off strong, it doesn’t hesitate at all, and when I rev it up it doesn’t feel or sound like its missing or anything... at a constant speed of 20 to 30mhp it acts as if im not getting enough fuel or air or something. It’ll just sorter lurch and stutter as I drive. I’m thinking it’s maybe the transmission with that one.. The fluid is still red and up to level and all. It’s really starting to seem like as soon as one problem goes away the next is right there to take over
Cost of car 1400.00 (2004) 97 SSE Anniversary Edition
Rebuilt transmission 1900.00 (2004)
Rebuilt lower block engine 900.00 (2006)
Transmission replacement used 1300.00 (2006)
UIM/LIM replacement 350.00 (2007)
Right half axle, motor mounts, transmission mounts, o2 sensors, wires, plugs, MAP sensor, starter 700.00 (2007)
Attachment 51069
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Car still running like crap! How does such a nice looking car be so much of a problem? I mean I don’t dog it out or anything. I just don’t understand. Should I keep it or let it go? I’ll decide on all of your input. This car is breaking me and never acts like a regular small problematic vehicle it's always a major thing when something is wrong with it


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