10-24-2012, 02:13 PM
E39 540i Sport
Location: Virginia Beach
Join Date: Jul 2012
Mein Auto: 2003 540i w/Sport Package
***This is for my reference to test later when Im off, not easy going from post to post on iphone**
Test charging system via dash:
Hold down the right button (about 10 seconds) until test 01 shows
Press the left button to get the results of test 1 (your VIN)
Add up the last five VIN digits, e.g., GZ12345 = 1+2+3+4+5=15
Press the right button to go to any LOCK=ON display
Note: This is different than the instructions which say to go to test #19, IIRC
Press the left button until it displays that number (15 in this example)
With that number displayed (e.g., 15), now press the right button (this should unlock the display)
To see alternator output, press the right button to get to test #09
Press the left button to view the results (e.g., 13.7 volts at idle)
Normal battery vlotage at 1000 RPM is 13.5+.
**With car off to test battery do above ^
test - 12.6 V - charged; 12.4 V - 75% charged; 12.2 V 50% charge; 12 V - 25% charged; 11.7 or less fully discharged.
**Check this BEFORE you start or charge the battery because you want to check it BEFORE it receives a "surface charge"...which can give you an untrue reading of the battery's health.
If you run TEST 9 with the engine running...you will get an idea of the car's charging system voltage. With the engine running, you should have voltage numbers between 12.8 - 14+ volts....this is required since you have a 12 volt battery...in order to "replenish" the battery, it needs to receive more than it gives
- Here's quick test............. When you turn on the ignition does the temperature gauge go all the way to red?
If this is the case I've saved you a lot of diagnostic time. You can find and replace the coolant temp sensor (It should be burned up) but you will need schematics to find the fuse that it gets a signal from. I believe the fuse was located in the fuse box under the cabin filter on the passenger side of the engine bay.
- looked under the filter in the engine on the passenger side and found a whole new world of electronics. There is a light brown box with about 7 fuses. All of them are 30's, the little box is hard to open but u will get it. pull out all the fuses and change the burnt one. disconnect the battery for 10 min and then start the car.
Last edited by Ktaylor757; 10-24-2012 at 03:01 PM.
Reason: added for personal reference