Unlocking the Secret Menu Options on the BMW E39 M5

One of the great things about owning a BMW is that it is virtually impossible to know everything about the car. The amount of esoteric knowledge seems infinite, and its possible to turn the ownership experience into a full-scale hobby rather than just transportation. A case in point is the ability to access lots of data by unlocking the navigation and dashboard displays of the BMW E39 5 series.

Why do I call it secret? BMW never told owners about these options. It’s not in the owner’s manual, nor any official documentation I’ve ever seen. The same holds true for all late model BMWs since they share similar electronics, though I can’t vouch for the exact unlocking sequence for other models.

All modern cars are rolling computers and have been for a couple of decades. Every car sold in the U.S. since 1996 is what’s known as On-Board Diagnostics (OBD-II) compliant. This means that the car’s computer can share in a standardized way a great deal of information on how the various systems in the vehicle are operating. Dealers access this information during a service visit, for example. So do gas stations when they do  mandated state emissions testing.

Apparently BMW saw no reason to tell owners how they can see some of this data themselves. Want to know things like battery voltage, air/fuel mixture and how to change the warning sounds your car makes? How about latitude and longitude, g-force in the cabin or the GPS satellite tracking your car? It’s all inside the car’s brain, and you can access if you spend some time online in excellent forums like the M5Board.com, Bimmerfest.com and Bimmerforums.com.

Here’s how to unlock the navigation display:

1)Buy an M5

2)Turn the key on (engine running/moving is OK, not required)

3) Press Menu, then Set to enter the Settings screen.

4) Press-hold the menu button. The display will instantly change back to the menu screen, but keep holding the menu button in for about 15 seconds and you’ll get to the Status screen. There are several options there, including “Telematics” which probably only applies if you have the phone option, and Video System which only applies if you have the European model which allows you to watch TV.

5) The cool stuff is under “GPS” and “Sensors”. Once you get to the GPS screen, you choose “Function” to see “tracking info” which will tell you which satellites the GPS is watching at the moment, and how many. Another function shows you the GPS status – lat, lon, speed, etc.

Here’s how to unlock the test modes in the dashboard cluster:

1) Key to ignition pos 2 (no need to start engine).
2) Fasten the seat belt to get rid of the “Fasten Seat Belt” message.
3) Press the right button on the instrument panel, and hold it until “TEST-NR. 01” comes up (5 to 10 seconds).
4) Press the left button on the instrument panel, and the vehicle id comes up (last 7 digits of VIN).
5) Add up the last 5 digits to get the “unlock code”, e.g. the unlock code for “AB12345” would be 15 (1+2+3+4+5).
6) Repeatedly press the right button until “TEST-NR. 19” appears.
7) Press left button -> “LOCK : ON”
8. Repeatedly press left button until “LOCK : xx” appears, where “xx” is your unlock code.
9. Press the right button. All modes are unlocked now.

Many owners probably don’t care about this information, and some of it is admittedly pretty arcane (although the satellite ID is pretty cool). I found out about unlocking this information when I needed to test the voltage of my battery (test 09), which eventually needed replacement. Test 06 gives you a read of fuel level in liters for both left and right tanks. This is especially handy if the analog fuel gauge starts to stick and becomes inaccurate, which is a known issue with the E39.

I also hope to use test 04, which measures exact fuel consumption. That reading can be used to compute whether the Mass Air Fuel (MAF) sensors are operating at peak efficiency. This is done via a mathematic formula that requires controlling for barometric pressure and the external temperature at the time of the test.

See what I mean about becoming a full-scale hobby? Happy Thanksgiving everyone.

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