p1406 on 97 GA 3.1

[3100]

Hi guys, sorry for posting my question here, I did try on GA forum which for some reason is very slow recently.

Here is one interesting problem.

Got this code 1406 for EGR pintle position circuit, but the fun part is that the freeze frame registered 72 In Hg for manifold absolute pressure at the time of the mentioned code activation. All other engine parameters were normal can't exactly remember what they were but they were normal. Also no other codes. Not even for MAP.

I know that there is 34 step procedure to test this but maybe some of you already had fun with this and maybe know some short cuts what to look for.

I did have another egr valve in my tool box, but the code is back after 20 days. Both egr valves looked clean. I did check el diagram for egr, and map sensors values (voltage vs In Hg). I know that 72 In Hg is impossible number since map can't be greater than the outside ambient pressure which is about 30 in hg.

here is something interesting: please look at this site and look at the map/voltage vs in Hg table
http://www.aa1car.com/library/map_sensors.htm
then I extended that table and concluded that in order for pcm to register signal of 72 in hg, map sensor had to be sending signal close to 12v vs 5 or 4.7V max, am I barking at the right tree here? Thank you for any advices in advance - 3100
What even makes all this even more beautiful is that this is intermittent problem obviously, and I did try commanding EGR to open and close with my scanner and it worked fine. I have couple things on my mind what could cause this, but would like to hear your opinions first and see if they match.

[tblake]

So you concluded that for the MAP to send a signal of 72 inches that the signal voltage would be around 12v? Sounds like B+ may be leaking into your signal wire from the MAP to the PCM. Check for that with a multimeter.

I would remove the PCM, clean the contacts with electrical contact cleaner and put it back in. Not sure where it is located on a grand am though.

[3100]

Originally Posted by tblake

So you concluded that for the MAP to send a signal of 72 inches that the signal voltage would be around 12v? Sounds like B+ may be leaking into your signal wire from the MAP to the PCM. Check for that with a multimeter.

I would remove the PCM, clean the contacts with electrical contact cleaner and put it back in. Not sure where it is located on a grand am though.

I was thinking the same thing but according to diagram map sensor is not getting 12 V just 5v reference

thank you for your input

[BNaylor]

3100,

I don't mind you posting at the Grand Prix forum due to the circumstances but we do not allow two threads on the same issue running at two different forums on AF at the same time. You have a similar thread at Grand Am.


Thread at Grand Am Forum