cww516 Posted January 5, 2018 Share Posted January 5, 2018 I don't suppose you have any way to track front O2 sensor output, do you? Either AFR or raw output? I'm not sure how quickly the ECM reacts to AFR changes as reported by the front O2 sensor, but if there's a crappy electrical connection causing the sensor to read low momentarily, I suppose that could do it as well. Not sure I'd start looking there, since you were getting the same code before they changed the sensor, but if you can log it, it's free, so you may as well. Link to comment Share on other sites More sharing options...
FLlegacy Posted January 5, 2018 Share Posted January 5, 2018 See if the problem is there in open or closed loop that will eliminate or point to the afr readings being off. Open loop doesn't use the afr, closed loop does. Link to comment Share on other sites More sharing options...
ehsnils Posted January 5, 2018 Share Posted January 5, 2018 Fuel pump starting to go bad? Checking fuel pressure while driving might reveal something. Link to comment Share on other sites More sharing options...
YeuEmMaiMai Posted January 5, 2018 Author Share Posted January 5, 2018 OK I will see if I can pull that parameter up on the data logger.. with the temps being in the -10F range working in a unheated detached garage... uh not going to happen. car runs well at pretty much anything despite the crap mileage. other things to note that even at steady cruise on flat road mileage readings are all over the place....where it used to be relatively steady.. Link to comment Share on other sites More sharing options...
dgoodhue Posted January 5, 2018 Share Posted January 5, 2018 ok got the data logger and found that short term fuel trim is randomly jumping up to 35%... that is just a tad bit aggressive.. I wouldn't concentrate on the short term corrections. As some who has done some tuning, I ignore those value (same goes for injector pulse width at anything beside WOT) In a properly running vehicle the short terms are all over the place anyways, as the ECM (in general) is always trying to keep the closed fueling at 14.7:1 during part throttle operation. Look at your O2 values. Link to comment Share on other sites More sharing options...
YeuEmMaiMai Posted January 5, 2018 Author Share Posted January 5, 2018 most of the time it is hanging at 3-6% and when it jumps up like that the car starts to stumble when idling Link to comment Share on other sites More sharing options...
YeuEmMaiMai Posted January 6, 2018 Author Share Posted January 6, 2018 OK took a look at front o2 and rear o2 reading and they are both updating at the same rate and look normal to me... next I looked at MAF readings and this is what I saw 1 at idle there is a fluctuation of 2-3 g/sec with some larger spikes and when those spikes occur when coming to a stop, it wants to kill the car... second does anyone know of a good software in windows that I can use with the car? I have a few and they all seem rather limited... Link to comment Share on other sites More sharing options...
Perscitus Posted January 6, 2018 Share Posted January 6, 2018 Windows Vista/7/8/10 - FreeSSM or RomRaider (logger module) with a VAG-COM or Tactrix OPv2 cable. Alternatively, Android 5/6/7.x phone or tablet: BtSsm and VAG-COM, OBDLink LX/MX dongle, BtSsm dongle or Tactrix OPv2 cable. Link to comment Share on other sites More sharing options...
YeuEmMaiMai Posted January 6, 2018 Author Share Posted January 6, 2018 I have the cable and I will get the software Link to comment Share on other sites More sharing options...
YeuEmMaiMai Posted January 9, 2018 Author Share Posted January 9, 2018 OK car is at the dealer again and this is what I told them 1. When car wants to stall, MAF readings spike up at the time of the event. a. MAF readings are not stable at idle (they should fluctuate only a tiny amount, not by .3-.6 grams or more) b. At constant cruise on level surface instant fuel economy is ALL OVER the place even when throttle is not moving. 2. Car takes excessively long time to warm up. 3. Upstream o2 sensor has already been replaced. 4. I do not do sudden stops as I (when possible) let the car coast down and then gently apply brakes. the car has stalled under these conditions.. My diagnosis is that there is a MAF problem or a vacuum leak and I am willing to bet MAF sensor failure. I do not have any EVAP codes along with the P0171 I know that the purge solenoid is working. I never add more fuel after the first click, I know my charcoal canister is not saturated with fuel overflow. O2 data indicates that both sensors are working and they are updating at a very normal rate. I went out to the car and checked all of my hoses and intake tract and nothing was loose or missing or out of place This leads me back to MAF sensor problems Link to comment Share on other sites More sharing options...
cww516 Posted January 9, 2018 Share Posted January 9, 2018 They'll probably have to do some diagnosing just to say they did, but it seems like you got it pretty well tracked down for them. Link to comment Share on other sites More sharing options...
YeuEmMaiMai Posted January 9, 2018 Author Share Posted January 9, 2018 well at least I got an 18 outback to drive... nice overall but one thing that is missing that I use a lot is the visor extenders Link to comment Share on other sites More sharing options...
YeuEmMaiMai Posted January 12, 2018 Author Share Posted January 12, 2018 Still no word as to what is up with the car.... Link to comment Share on other sites More sharing options...
YeuEmMaiMai Posted January 18, 2018 Author Share Posted January 18, 2018 OK called up the Subaru dealer and this is what they initially said 1. We replaced a much of parts and the Service Manager is driving your car when asked to what parts were replaced it changed to 2. We did not replace any parts on the car and the service manager is driving your car when asked about the P0171 code... 3. We don't know we did a relearn procedure on the car and the service manager is driving your car okay.... they stated that it would be ready by Friday :/ Link to comment Share on other sites More sharing options...
YeuEmMaiMai Posted January 20, 2018 Author Share Posted January 20, 2018 Go car back, claim n.p.f., car runs smooth like it was new, fuel mileage is back where it should be for the most part. Car no longer tries to stall out when coasting to a stop.... stated that they updated all the firmware on the car and did an relearn procedure on the car... hopefully this is the end of it. Link to comment Share on other sites More sharing options...
YeuEmMaiMai Posted January 21, 2018 Author Share Posted January 21, 2018 Scrap that.... car threw an unknown code for network error and now no power... U0073 Link to comment Share on other sites More sharing options...
ehsnils Posted January 21, 2018 Share Posted January 21, 2018 Scrap that.... car threw an unknown code for network error and now no power... U0073 "U0073 CAN Failure, Bus 'OFF' Detection" And here's someone else that's having the same problem: http://www.subaruoutback.org/forums/66-problems-maintenance/52146-greetings-newbie-cel-u0073.html So if you have something plugged in to the OBD connector while driving then that may be the culprit. If not then you have a wiring issue or a bad ECU somewhere. Link to comment Share on other sites More sharing options...
ehsnils Posted January 21, 2018 Share Posted January 21, 2018 Searching around - there are people that got this problem when they have replaced some lamps with LED lamps. Link to comment Share on other sites More sharing options...
cww516 Posted January 21, 2018 Share Posted January 21, 2018 I'd unplug your logging hardware (I know you've said before if it's hardwired or Bluetooth, but that's on a different page, and I'm already committed to this reply) and hope that fixes it. That code looks to be a generic "hey, one of the modules isn't on the network" code, nothing to indicate which module specifically. Considering those things don't typically just up and unplug themselves, my best guess is that at some point in the development cycle, Subaru's software folks changed the threshold voltages for what's recognized as high (1) or low (0). Looks like the ISO 11898 standard uses the same 5V signal with a pair of 120 ohm terminating resistors like I'm used to seeing in J1939 systems, so it's probably a safe assumption that the voltage thresholds work similarly as well. If you connect something to the bus that changes the resistance in the circuit enough, it could be "erasing" messages that are already pretty close to those voltage thresholds (which is what the terminating resistors in the ECU and the VDC module are supposed to do) by reducing the voltage levels of those messages below the "high" threshold. The vacation pics say you should see 56 to 64 ohms resistance on a closed circuit (can high to can low, so pin 6 to pin 14 on the OBDII connector, for example), which is only about a 5% tolerance, so there's not a whole lot of wiggle room. Vehicle electronics deep-dive aside, the process for diagnosing a canbus fault is basically open the backbone somewhere, look for continuity/120 ohms resistance in each direction, then repeat the process in the "bad" direction until you find the branch that's causing the issue. Looks like the only places to split the backbone are the ECU, VDC module, and BIU, so you'd be unplugging every branch node and re-checking those conditions with one module connected at a time. Straightforward, but tedious as all get out, and getting to all of the modules won't be fun either. Link to comment Share on other sites More sharing options...
YeuEmMaiMai Posted January 21, 2018 Author Share Posted January 21, 2018 "U0073 CAN Failure, Bus 'OFF' Detection" And here's someone else that's having the same problem: http://www.subaruoutback.org/forums/66-problems-maintenance/52146-greetings-newbie-cel-u0073.html So if you have something plugged in to the OBD connector while driving then that may be the culprit. If not then you have a wiring issue or a bad ECU somewhere. ironically no, but the obd2 scanner has been plugged into the port before all this went down for 2 years no issue. LED interior lights are also 2 years old and they are all still working just fine...all of this started after they replaced the transmission at 40K, now at 45k. there are no non stick exterior LEDS installed at this time when the car crapped it's self, the VDC light was lit up as well. It is no longer lit up and the code has gone to historic as well. CEL remains on but no active codes Link to comment Share on other sites More sharing options...
ehsnils Posted January 21, 2018 Share Posted January 21, 2018 ironically no, but the obd2 scanner has been plugged into the port before all this went down for 2 years no issue. LED interior lights are also 2 years old.. and they are all still working just fine...all of this started after they replaced the transmission at 40K, now at 45k when the car crapped it's self, the VDC light was lit up as well. It is no longer lit up and the code has gone to historic as well. CEL remains on but no active codes This seems to be similar to what others have experienced in the threads I found - device plugged in for years suddenly starts to cause problems. Either it's the plugged in device or it's the vehicle that has aged and drifted. I experienced problems myself when I used an OBD-II extension cord once so I put that aside and did a direct connection. As I see it the primary cause is that Subaru has decided to put the backbone CAN bus exposed in the OBD connector. It's cheaper but also comes with a risk of connected devices messing with the vehicle. Link to comment Share on other sites More sharing options...
YeuEmMaiMai Posted January 21, 2018 Author Share Posted January 21, 2018 Windows Vista/7/8/10 - FreeSSM or RomRaider (logger module) with a VAG-COM or Tactrix OPv2 cable. Alternatively, Android 5/6/7.x phone or tablet: BtSsm and VAG-COM, OBDLink LX/MX dongle, BtSsm dongle or Tactrix OPv2 cable. can you link me to the exact VAG cable that will work? FreeSSM will not work with the one I have... Intetrface test fails and no connect to car despite cable showing power Link to comment Share on other sites More sharing options...
ehsnils Posted January 21, 2018 Share Posted January 21, 2018 Assuming it's the '14 then you'd need the Tactrix 2.0 connector that talks CAN, the VAG-COM is as far as I know only able to do K-line which is for older vehicles. Link to comment Share on other sites More sharing options...
YeuEmMaiMai Posted January 21, 2018 Author Share Posted January 21, 2018 yeah that thing is over $200 now, i will see if i can get one, and what do i need besides the dongle that connects to the OBS2 port? Link to comment Share on other sites More sharing options...
Perscitus Posted January 21, 2018 Share Posted January 21, 2018 Assuming it's the '14 then you'd need the Tactrix 2.0 connector that talks CAN, the VAG-COM is as far as I know only able to do K-line which is for older vehicles.Yes, this might be the case, I think for 2014s on SSM via Kline through an OBDII pin went bye bye so the only option is SSM over CAN. For that you can use Tactrix OPv2, OBDLink LX, MX. Tactrix OPv2 is by far the best option though. Link to comment Share on other sites More sharing options...
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