Chasing down possible gremlins! Please help.

[SINCITY192]

This is the first 2003 BMW 325i I have ever owned with that being said. I am a skilled wrench'er and I am not afraid of any jobs.
But this BMW has me rethinking my whole life!
When I brought it, and it would not start... I traced that down to a fuel pump, changed it out and was able to get it running.

Since I have had the car it has had these codes:
P0103 (2 of 2) Generic Pending - Mass or Volume Air Flow Circuit High Input
P0103 (1 of 2) Generic Stored - Mass or Volume Air Flow Circuit High Input

I have brought a after market sensor to replace and it still has the code even after clearing it with my INNOVA Scanner. (I do not have a BMW scanner)
The car drives but down shifts into first terribly. It Jerks every time when coming down to the first gear when coming to a stop.
I know this is a transmission issue any insight on where I can get the stuff I will need to change out the solenoids, would be great.
My biggest issue lately is i have been getting a issue after my wife takes the car, it never fails she comes back and it does not respond to the pedal at all.
Car will start but will not rev. I would normally point to the TB sensor (since I do not have a cable) and the wireless design is knew to me.
But a issue where my horn stopped working as well as other equipment that runs off of the fuses 5-15
When checking for power at the fuse box in the car, those fuses 5-15 have a dim light but the fuses are not blown.
Everything on those fuses do not work in the car or works when it wants to like the radio will come on but will turn off at will.
The heated seats use to work but now they don't all tied to the fuses 5-15 I am assuming the test light almost barely show power.
I also believe this can be tied to my pedal choosing to when it wants to respond. I usually have to turn the car off. Press down on the gas all the way and hold for 20 secs. Then start the car with the pedal still held down. The car will start and idle up and return to normal. I also noticed this happens because my wife will run the car until its barely any gas left in there. But never until its empty.
Any Direction advise, would greatly be appreciated.

BTW: The horn fuses were not blown. Number 5 was a dim light and 55 was a bright light, a visual check of the fuses and its not blown.

Thank you
Sincere

[bluptgm3]

Check the basics, have your battery checked out. Check the fluid level, top up with distilled water as required and charge on low amperage overnight


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[Muzz258]

Hi. Welcome to the forum.

Yes the E46's are rolling computers and don't like low voltages, so you will usually get a "charge the battery" or a "check the alternator is charging" replay. It's surprising how many times a new battery fixes problems on an E46. So, jump to number 4 below and fix the voltage problems, it might just sort all your problems.

1) P0103 MAF signal high. Check that the female connections in the MAF connector are not splayed apart stopping a good connection. Then check for wire continuity between the MAF and the engine computer (DME). Wiring diagrams can be found in https://www.newtis.info/tisv2/a/en/ enter the last 7 digits of your VIN number into the search box and it will find the information for your car.

2) Terrible downshift into first. The automatic transmission computer (EGS) uses many, many different signals from the engine or ABS to determine when to shift. The P0103 code could be the cause of your problem. It might not be too, so fix the P0103 first and see if the issue remains. Do you have a scanner that can read the EGS trouble codes and look at the transmission live data? If not, I recommend that you download the BMW software INPA (Free), install it onto a windows laptop and buy the special cables (cheap). This gives you a very good BMW scanner that reads all computers in the car. Get INPA from here https://www.bimmerforums.com/forum/s...xperimentation

3) Car not responding to the peddle. If the throttle body or peddle sensor have problems, they typically raise trouble codes. As you don't have any codes its lightly to be something else. Don't know what at this stage.

4) Fuses 5 to 15. It took some time but I found the common link. Fuses 4 to 15 are feed from the same contact in the ignition switch. See below diagram https://www.newtis.info/tisv2/a/en/e46-325i-lim/npxc9RQ
It in turn is fed from fuse F106 see diagram https://www.newtis.info/tisv2/a/en/e46-325i-lim/cAtxASu
F106 is located behind the glove box see diagram https://www.newtis.info/tisv2/a/en/e46-325i-lim/Vw04WE5
F106 looks like it is bolted in place, so your problem could simply be a loose nut. Remember to disconnect the battery before trying to tighten the nut. There is not much in the way of protection (fuses) between that location and the battery and a slipped wrench could cause one hell of a spark and lots of damage.

Now that you have the path, get a multi-meter so you can measure DC volts as well as Ohms. You can then fault find voltage until you get a solid 12 V DC. Then if needed you can isolate the voltage source and backtrack the continuity of the wires and connections with the ohm meter to find the fault.

[earlster]

I know this is an old thread, but did you ever figure out the horn/heated seat issue? I'm having the same problem. Also, when the headlights are on auto and I press the horn, the headlights flicker. But if they are on full (all the way to the right), they work just fine.

[earlster]

In case anybody comes across this again, it was the ignition switch. Plenty of DIY videos on youtube. Took me quite a bit to diagnose, came across 5V at the fuses mentioned by the OP. Kept chasing it down looking at diagrams in ISTA and eventually figured it out. Now that I know and there are so many threads about ignition switch, it's obvious.