jamesc

freeze frame from P0106 code P1143, sorry bout the big pics i did downsize them

thanks guys i appreciate any and all help. this thing really has me puzzled not to mention i have a 632" all aluminum race engine i'm helping a friend with that's giving me grief it's tough trying to fix things over the phone, i'll try to recap a little >clear code >connect and setup scanner >turn key on view data, everything shows values but the map reads zero >start engine, map reads 30.1" (atmospheric) and immediately sets pending code P0106, don't know how long it will stay there at 30.1 but i let it idle a bit before bumping throttle >bump throttle, the source valve immediately switches and MAP drops to 8.5" >if i restart a few times it will set the code hard without even driving and when it hard sets the freeze frame shows the MAP at 30.1 this is what was making me think the ECU didn't want to see the 30.1 for any length of time after starting which is why i figured as a test i would route manifold direct. this way i figured it wouldn't set a code until it cycled the source valve to look at atmospheric again which would set a different code. i don't know what the cycle rate is but at sometime after starting i would think it needs to occasionally look at atmospheric. so having done that it really threw me a curve when it immediately set the P1143 code (low value) when i started the engine. so now it's pissed if it sees either 30.1 or 8.5 i know i have to be missing something simple here but it seems counter intuitive. it triggers a code both low or high depending on how the vacuum is routed i can't get it to not trigger some code. i checked the source valve though i didn't use air pressure or vacuum pump i just blew or sucked on the hose (yea i know) and it seemed to shift tight which is kinda proved out by the MAP readings seen when it cycles when started and throttle bumped. i checked the filters, the hoses are new and i feel confident about the system vacuum integrity as mentioned the measured voltage values are off but the indicated MAP values both atmospheric and manifold are within range the "idle switch" is still an unknown though afaik there is no actual switch just the normal potentiometer and the TPS values are solid at 0-100% the fact that the source valve switches as soon as the throttle is bumped leads me to believe the "idle switch" is working correctly

update, my friend has an ancient subaru select scanner but didn't have the exact module for this car. we attempted to use it in an effort to see of the idle "switch" indication was correct but couldn't get the scanner to work. i'm inclined to think this isn't an issue though because the TPS values are good at 0-100 and the source solenoid switches to manifold as soon as the throttle is bumped while running. because the freeze frame data shows a value of 30.1" when the code sets while the engine is running i decided to try running the manifold directly to the sensor. i erased the P0106, rerouted the hose then drove the car. it is NOW setting code P1143 (and only this one) which is sensor performance low. i'm going in circles because this new code makes me think that the ECU WANTS to see atmospheric value when first started until the throttle is opened but yet when the system is correctly routed it's setting the code because it's 30.1" i can now duplicate the CEL condition. after erased and everything properly routed on the very first start it will set P0106 pending and then without driving it a few subsequent starts will set the P0106 as a hard code. the MAP does track correctly once the solenoid shifts to the manifold though i haven't perfectly followed the diagnostic procedures i think i've been pretty thorough and can't help but think this ECU is brain damaged this thing is driving me nuts

can't say for certain that it's not an intermittent problem but everything has been inspected pretty thoroughly and i've never seen a problem while driving with the scanner hooked up

no engine work, hose routing is simple and correct. i've been referencing Alldata, Mitchell and FSM information which best i can tell is what Alldata has. i did bench check the sources valve and found it to be OK. what's throwing me off is that unless i'm screwing something up the absolute pressure values indicated with the scanner fall within range

1999 legacy outback 2.5l giving me fits, owned car a couple years. 6 months ago CEL comes on with P0106. this is the ONLY code car has ever thrown visual inspection checks OK and no driveability problems replaced MAP with boneyard part, no change inspect vacuum hoses no apparent problems but replaced anyhow (checked filter) checked TPS adjustment per friend (previous Subaru tech) bench checked sources solenoid, checks OK peformed solenoid test with underdash connector, checks OK gave up for months now it's due for inspection CEL light will sometimes go out checked continuity/for grounds on all three lines from MAP to ECU, all good checked MAP voltage, 5.1 reference, 3.75 KOEO, 1.49 at idle, specs call for 3.9-4.1 KOEO and 2.0-2.3 at idle i understand these voltages are out of spec the KOEO i feel may be OK but the idle is low that said the pressure values indicated by an actron CP9580A and OTC Genisys fall within acceptable range manifold vacuum measured at sources solenoid is approx 20" at idle MAP sensor tracks while driving TPS tracks properly from 0% to 100% my friend worked for Subaru for years and is a skilled tech (as am i but not experienced with subaru) he hasn't personally checked the car i've been bouncing stuff off him and he's stumped as well two points to note, i do not have the ability to do the "idle switch signal" test though i "assume" because the TPS tracks from 0-100 that should be OK second is that with either scanner hooked up when the key is cycled on neither gives a MAP value it just shows "0" though the other values come up and TPS will track. when the engine is started the MAP will show an atmospheric value of approx 30.1" (102kPa) , then when the throttle is bumped and the solenoid switches it will show a manifold value of 8.5" (29kPa). i'm assuming this is how the system is supposed to work where it reads atmospheric until the TPS is bumped though i'm not certain. the fact that the MAP shows no value with just KOEO concerns me i would "think" it should read but of course it does read once the engine is started. a new MAP sensor is $300 and has to be ordered, i'm not going to "try" a new one at that cost. ordered another used one off ebag will try that though i'm not very convinced the sensor was ever an issue. after all the initial tests and swapping the sensor my first impression was that the ECU was the issue but i just let it go because the car ran Ok and initial checkes showed no problems. now i'm down to trying another MAP and if that doesen't work will have to try an ECU what am i missing? thanks and sorry for the long winded first post