ToreDL87 Posted January 23, 2020 Report Share Posted January 23, 2020 (edited) New member here! Despite circumstances I'm pleased to be here As for the issue: '03 E46 318D M47TUD20 Euro 3, #PK86252 , German import, pre-facelift I believe? EGR delete, checked vacuum hoses with tester (no leaks), new air filter, new diesel filter and so forth. As title states, I'm not getting any MAF reading (but IAT works perfectly) on my OBD2 reader (one made specific for BMW). Tried new MAF sensors, incl Bosch (My MAF plug is 4-pin) but still no go, previous owner tried a bunch of different ones too, to the point that he doesn't remember which one is original (so I can't check part #) Deleted error code between each MAF swap... still no go, error goes away for that outing, but pops up when cycling the ignition (turning the car off/on). It's not that it's getting a low or high reading, it's that it's getting absolutely no reading at all, and I mean dead 0, while IAT just keeps chugging along... bad MAF sensors usually reads high or low, I get that, but all the ones I'm trying = Nothing... what the.. Thought maybe the MAF>ECU input wire is botched, but when I found that IAT uses the same wire... Heck I even tried a Euro 4 sensor just to see if I could get a reading = Still no dice. Been trying to check if maybe I need re-coding for new MAF despite c.a the whole intrawebs saying a '03 pre-face doesnt need it. But solid info on E46 is the absolute hardest to source out of the many cars I've worked on over the years, tried on that newtis site for BMW wiring but it shows like 20 different MAF's for my #VIN, all of the DDE's etc, checked all the "insert name"-parts sites, they show all of the different MAF sensors as well, 314, 529, 527 etc nothing actually definite for my specific car, tried realoem, it says I need 314 (i have a bosch one laying around) but it's 5-pin, my car has a 4-pin (as in, 4-wire) MAF plug, not 5-pin, obviously 4-pin plug wont fit 5-pin sensor = sodded. Is there anything that can go wrong on these things that makes ECU totally ignore MAF or something? Only thing I can think of is reset SES (most of that's been done anyway)? ..At complete wits end! Edited January 24, 2020 by ToreDL87 Link to comment Share on other sites More sharing options...
E46Driver330Ci Posted February 25, 2020 Report Share Posted February 25, 2020 Can you not ask a dealer what the part number should be? If they give you the same as realoem, then the car was probably modded. It was modded because the MAF wasn't working. What does your BMW specific reader say the error was? If the error means no MAF reading, then that could be because the 5th wire was was missing. I'd follow the MAF cable to the end to see if any chopping up had taken place Link to comment Share on other sites More sharing options...
nickbor34 Posted April 7, 2021 Report Share Posted April 7, 2021 (edited) I recommend reading old catalogs or books about details. You can find the old markings in use today. Edited April 7, 2021 by nickbor34 Link to comment Share on other sites More sharing options...
