E36 OBC tricks

OBC information and instrument cluster testing for E36

E36 On-BoardComputer (OBC) Hidden Codes and Tests

There are many interesting functions available on the E36 OBC that are not documented in the owner's manual, including changing the language of the display. The procedures described here work on a 19'97 328iC, which has the upgraded OBC – they may work on other models of similar vintage.

There are some links at the bottom of the page for information on other OBCs, and for setting the language if you don't have the OBC.

Contents:

• Programming the Display Order

• Accessing Data

• Unlock the Display

• Test Codes

• Setting the Country Code

Programming the OBC to Display Contents in a Desired Order

When you repeatedly press in on the turn signal stalk, the OBC display cycles through the various information types that it has in memory. The default sequence is; CONSUM1, CONSUM2, EXT. TEMP, SPEED, LIMIT, DIST and TIMER.

If you want to change the display order, use the following procedure.

Press in and hold the turn stalk for about 5 seconds.

The OBC display will change to Prog 1.

Press the button corresponding to the first function you would like to have displayed in the sequence. For example, if you would like the outside temperature to be displayed first, press the TEMP button. The display will then change to Prog2. Continue pressing the OBC buttons in the order you want, up through nine entries. You don't have to enter all nine – if you would like the display to cycle only between TEMP and RANGE, simply enter those two items as Prog 1 and Prog 2.

When finished, press the SET/RES button to store the sequence in memory. To revert to the default order, simply press SET/RES as soon as Prog 1 is displayed.

Accessing Data in the OBC

The OBC contains a lot of data, and displays the data in a manner determined by the country code that is stored in it. The technique to access this data is as follows. NOTE: To access codes other than 1, 10, 14, 19, and 21, you have to first unlock the OBC, using the procedure described below.

1. Press the 1000 and 10 keys simultaneously. You should see “Test-Nr.:” appear in the display.

2. From the table below, enter a test code number, using the number keys, followed by the SET/RES key.

3. Read the results.

4. For test numbers 10 and 11, enter a new value (if desired) and press SET/RES.

5. Return to the normal display functions by pressing CHECK or any other key.  

Unlock the Display.

Most of the test sequences require you to first unlock the display before. Enter test code 19 using the above procedure. The display should read LOCK: ON. Then enter an unlocking code consisting of the sum of the current month plus date (for example, if today is July 11, enter 18). Then press SET/RES, and the OBC is now unlocked.

Test Codes.

Following is a listing of the available tests, along with with notes as to what I think each test means. Note that the display uses European conventions for decimals (i.e., the number 61,7 is 61.7 for us Americans). You will see that I don't have good explanations for several of these test codes -- if you have any information that can help me make this table more complete, please email me at tech@bimmerinfo.com

Notes:

#20 - The factor is used to correct the OBC Avg Fuel Consumption figure to reality. If your OBC is off a bit, fill it UP totally and then run the tank down and refill. Then calculate your Actual MPG. Now enter test #20 get the old Correction Factor. NEW CF = OLD CF *(Actual MPG/OBC MPG)

Setting the Country Code.

If your OBC suddenly starts displaying everything in German, and you would like to put it back to English, use test sequence number 10. Once you're into test number 10, press the 1 key several times, and you'll see the display cycle through various country options. For example, 0is for Germany (the display reads LAND:0 D * - I assume D stands for Deutschland). As you cycle through the options, you'll see choices for the Great Britain, USA, France, Canada, etc. Once the display is on the country you want, press the SET/RES key to store your choice into memory – for US drivers the display should be set to LAND: 2 USA *. Then press the CHECK key, and the display will reflect the units of the country you've chosen.

Instrument Panel Tests

With the engine off, press and hold the trip mileage reset button, and then turn the key to accessory position 2 (OBC and radio come on). The LED display on the instrument panel (which normally is the odometer) will change to tESt01 and then will begin to cycle through several displays. Release the button. The display will continue to cycle through several displays.

Finally, all LED elements will light, and all gauges will cycle once.

You can press the mileage-reset button again to access more tests.

Tests 2 through 4 are always unlocked and available.

Tests 5 through 14 are normally locked, To access these you must first unlock the display-using test 15. Otherwise the display simply shows: --------.