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    1. Junior Member
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      05 Jetta/Daughter's car
      06-23-2019 05:08 PM #1
      I have another thread I started in the GolfV and JettaV forum and thought maybe I should have placed it here. The title is "05 Jetta P0016 & P0102 yup, me too!" I can copy and past it to this forum if that is better, or the mods could move it. I just don't want to have 62 threads in 150 different places, I don't want to be the PIA new guy.

      Any help or direction is much appreciated.

      Thanks, Jim
      Last edited by Jgger; 06-23-2019 at 09:34 PM.

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    3. Junior Member
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      05 Jetta/Daughter's car
      06-23-2019 09:28 PM #2
      So, if I have a bad upstream o2 sensor would that cancel the Maf from having any output? Since it would be running in closed loop or default program is why I ask. I have no signal from either sensor and the up stream o2 is the primary source of info. Or am I full of beans?

    4. Member
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      06-27-2019 05:26 PM #3
      Check with the Torque app. There is Fuel Status add-on display under the Real-time Information. Check online when the car is cold started. Drive it down to warm up the engine and check again. If the sensor is sending incorrect temperature data, the ECU will never shift to closed loop.

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    6. Junior Member
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      05 Jetta/Daughter's car
      06-28-2019 01:08 AM #4
      Thanks for the reply.

      I have cleared codes and have re checked, still getting the same codes on Torque. What it says is "closed loop using 1 o2 sensor (feedback fault)". That is in the fuel system setting.

      Also it says, "secondary air status from outside air or turned off"

      The o2 sensor that is being read is the down stream or B1S2, there is no signal being read from B1S1 like it should be.

      So the question is will the pcm turn off or not read the information from the up stream o2 sensor if it is also not getting a reading from the MAP or MAF?

      Could this be an ECM fuse issue? I can't find a layout for the fuse panel to even check that. It seems weird that I am not getting any feed back from the MAP, MAF, or B1S1 O2 Sensor. That is why I'm thinking the computer is just ignoring those 3 sensors as part of the closed loop program.

      I will add that this car has a "less than optimum " battery, so test results may be iffy at best. I will probably pick up a new battery this weekend.

      Any help will be gladly accepted.
      Thanks, Jim

    7. Member
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      06-28-2019 05:19 PM #5
      Did you check the Fuel Status display if the ECU switches to closed loop when the engine is warmed up?

    8. Member
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      06-28-2019 06:51 PM #6
      Quote Originally Posted by Jgger View Post
      So the question is will the pcm turn off or not read the information from the up stream o2 sensor if it is also not getting a reading from the MAP or MAF?
      Not sure. MAP engines run in a different way than the MAF engines.

      Normally, the PCM reads all data coming from a sensor regardless of its condition. But it may chose to ignore the data when the sensor is causing an issue affecting engine performance. In all cases, if the sensor has proper wiring and voltage you should be able to diagnose it with VCDS. When the MAF or MAP sensor goes bad, the PCM sets a fault code and usually triggers the CEL. Not sure if your vehicle is a MAF or MAP engine. I think you should first scan the car for fault codes. If you want to check the O2 sensors, press Test Results in the main screen and wait for a minute for the Torgue to check all available sensors for readiness. There you will see real data (voltage, temp.) of all O2 sensors.

      Quote Originally Posted by Jgger View Post
      Could this be an ECM fuse issue? I can't find a layout for the fuse panel to even check that. It seems weird that I am not getting any feed back from the MAP, MAF, or B1S1 O2 Sensor. That is why I'm thinking the computer is just ignoring those 3 sensors as part of the closed loop program.
      A fuse causing the ECU to go out would completely stop the engine. The MAP sensors are not typically wired to a fuse and if they are, they shouldn't share a common fuse with the O2 sensor. Also the odds of MAF sensor and O2 sensor going bad the same time is little. The same applies to the wiring considering that they don't share the same wires. Still it won't hurt checking the fusebox. You don't actually need the layout. Just remove one by one and check if they are ok. Take a picture of the fusebox before starting in case you forget the correct pin. Then check the sensors like I described above.

    9. Junior Member
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      05 Jetta/Daughter's car
      06-28-2019 07:22 PM #7
      Thanks, will do and see what turns up. I will either be back with what fixed or a thousand more questions.

    10. Junior Member
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      07-01-2019 03:30 AM #8
      Ronny thanks for the help so far, I'm not convinced that my problems are actually the sensors.

      I put a new battery in it this weekend and was able to run some electrickery tests , now I'm really getting confused.

      I tested all the fuses in fuse box "B" the one under the hood. I also removed and wire brushed clean all the grounds I could find. Here is where it gets weird, all the fuses tested good , buuuut not all of them had 12volts going through them. Tested with the - lead clipped to the batt- key on and touched both sides of the fuse with the + lead.like I said all but 3 showed 12v. The fuse in slot 33 showed 5.3mV. That is for the fuel pump which also runs through a relay, so maybe that is right. Also slots 44 & 45 showed the same 5.3mV. but I am not sure what circuit they protect. That information, what slot handles what circuit, is apparently a high priority secret for Volkswagon because I can't find anyone who can cough it up!🤪

      Anyway I also tested the MAF sensor plug and I have reference voltage of about 4.9V plus ground to the ECM is good. However I am not getting the required 12V. for the power. I am getting the same mystery voltage of 5.3mV. ????? This is probably why I have no feedback info showing on my Torque app for the MAF sensor. I didn't have time to go over the o2 sensor but I'm guessing it is the same thing.

      Sorry for the long post, just trying to get all the info on here so maybe someone can help an old man out.

      Where do I need to go from here? What should I be looking at now. Don't want to just throw parts at it, that just makes my arm hurt and my daughter's bank account shrink.

      Just a side not for anyone looking at this for answers, DON'T BUY THE HAYNES BOOK, IT IS TOTAL CRAP.

      If you are still reading, thanks for looking and I will consider all suggestions.

      Thanks, Jim

    11. Member
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      07-01-2019 05:37 AM #9
      I think you should check the ECU. Reference voltages are provided by the ECU. If your car is Mk5, the ECU should be located under the windshield cowl. It is a well-known fact that the rain and humidity protection is not good there. Check the connector, remove and inspect for rust and signs of water ingress. Check wiring for bent, damaged wires.

    12. Junior Member
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      05 Jetta/Daughter's car
      07-01-2019 08:33 AM #10
      Oh boy, this is taking me to dark and scary places.

      When disconnecting anything from the ecu I need to first disconnect the battery, right?

      Now before I jump into the ecu, remember that I do have reference voltage and ground to and from the ecu from the maf plug. I am missing the 12 volt operating power, which should come from the fuse panel. So in the case of the maf, the ecu is doing it's job but the maf isn't powered up. Or am I off base here? Heck I'm not even sure that the fuse for the maf is located in the under hood box "B", I sure would feel better if I had a map or layout of both fuse panels.

      So my newest question would be:
      1. Is it "normal" for those 3 fuses to have such a low reading?
      2. If not, then what might cause that, a ground?

      Thanks again Ronny. Anybody else want to play? Haha!

      Thanks, Jim

    13. Member
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      07-01-2019 05:54 PM #11
      Yes, you should disconnect the battery.

      I am still unsure type of engine you have - MAF or MAP? I have little information on MAF engines. I thought the sensor should only have one voltage pin. It might take another power source from the fuse panel. You really don't need fuse layout. Just remove one-by-one, check, replace.

      I think low voltage like 4-5 mV on a fuse is not normal.

    14. Junior Member
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      07-01-2019 08:25 PM #12
      Well Ronny on this motor it has both a MAF & a MAP, I know it's weird. From all the research I have done neither one functions in the normal maf/map manner, but that is by design and I'm still trying to wrap my brain around that one.

      As for the 3 fuses that are reading low, one is for the fuel pump, which is working fine, so it may only show 12v when the pump is actually running. The source or circuit for the other 2 are unknown, so the layout would help me track that down. I suspect that one of them is the maf power because they both read 5.3mV.

      More to come......

      Thanks Jim

    15. Member
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      07-02-2019 02:38 AM #13
      What type of engine do you have?

    16. Junior Member
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      05 Jetta/Daughter's car
      07-02-2019 02:47 AM #14
      All I know is it is dohc 5 cylinder no turbo. Is that the question? Gas

      It is an 05 with a birthday of 06/2005
      Last edited by Jgger; 07-02-2019 at 02:04 PM.

    17. Junior Member
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      07-02-2019 02:50 AM #15
      That is dual overhead cam, stupid auto correct! Maybe that is because I am on a sohc motorcycle forum too.

    18. Junior Member
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      05 Jetta/Daughter's car
      07-05-2019 10:24 PM #16
      Ok since I am an IDIOT NOOB with VW's it takes me awhile th grasp what has been asked of me.

      The engine is indeed the 5 cylinder and it's a BGQ.

      I am still doing battle with this thing and can still use some help. I bought a used Bently book for it and am not ripping anything else apart until it arrives unless you guys give me some advice.

      I have read of others having the no 12v to the maf and the fix is to run an overlay wire. I need to find out where to source the 12v from as this looks like where I'm headed with the maf issue. COME ON MAILMAN, BRING ME MY BOOK!

      Thanks for reading.
      Jim

    19. Member
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      07-08-2019 04:00 AM #17
      PM'd you 'B' fuse diagram. Do you know codes of the OBD faults?

    20. Junior Member
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      05 Jetta/Daughter's car
      07-09-2019 09:01 AM #18
      P0102 and p0016 are the current codes along with the assorted misfires (all 5 cylinders at different times).

    21. Member
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      07-10-2019 04:07 PM #19
      Quote Originally Posted by Jgger View Post
      P0102 and p0016 are the current codes along with the assorted misfires (all 5 cylinders at different times).
      Are you sure P0016? P0016 is related to cam/crank timing chain. Chain elongation or a tooth skip could cause the code.

      P0102 - Mass Air Flow Circuit Low Input. It refers to MAF sensor signal frequency out of range. VW Malfunction Criteria says, MAF sensor signal is less than 66 μs. This is an indication of a bad sensor.

      I don't see any relation between P0016 and P0102.

      O2 sensor, like any other critical sensor, can cause the ECU to ignore MAF sensor outputs. This is typical when the ECU detects a severe performance problem and decides to switch limp mode on. But in your case the problem is, the MAF sensor signalling out of range and bad cam/crank correlation.

      I recommend you to continue your diagnosis with an experienced mechanic with capable diagnosis tools for checking the chain.

    22. Junior Member
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      05 Jetta/Daughter's car
      07-10-2019 10:15 PM #20
      Ronny, on the maf. It is supposed to have not only the signal voltage from the ecu, but also 12volt battery power. It is the 12volt battery power that is missing. So the maf may still be good but not being powered up. I need to find the source of the 12v. power and repair it to be able to test the maf.

      Now on the cam/crank correlation problem it can come from more than just stretch or jumped chain. The VVT solenoid had crap stuck in it possibly from a recent valve cover gasket change (by someone else). I cleaned it and it seemed to smooth out a bit. I would like to do a little more poking around and diagnosis before I spend money my daughter doesn't have. It may very well have a chain issue, I just need to put to bed a couple of other issues first to satisfy my old man brain!

      With no maf reading AND no o2 sensor reading I need to run down possible electrical issues before mechanical issues.

      Don't give up on me yet, you have been very helpful so far, so THANK YOU! After my Bently book arrives I will be able to check all that out.

      Thanks, Jim

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