Latest revision as of 08:59, 10 March 2013

The On Board Computer (OBC) was a digital meter unit offered by BMW. It provided live data such as time, average speed and fuel range, and was mounted in the centre console. If you want to add one to your E30, learn more about installing the OBC.

Types

6-button

The 6-button OBC unit was a standard upgrade from the analogue clock that is present in the E30 central column. This 6-button unit provides basic Time and Date functions, as well as setting reminders such as hourly alarms; a feature designed by BMW to remind the driver to turn on his radio for the news. How thoughtful.

13-button

The 13 button OBC was optional on 6 cylinder cars in the UK, and standard on all SE models. They continue to be an extremely desirable extra, and are a more popular retrofit due to their larger range of features compared to the 6-button unit.

Parts

The simplest OBC unit is a self-contained computer that requires only a wiring loom to the dash cluster, in order to read information such as speed. A standard addition is a secondary loom to control the car horn, and to provide access to an external temperature sensor. A gong was also featured to provide audible alerts. For the more advanced OBC a control relay is required, mounted above the main vehicle ECU, and an extra control stalk was available, to operate the OBC from the steering column.

Operation

For a full explanation of the OBC and how it's used, we've uploaded the instruction book for you.

Functions

The 6 button OBC has the following functions:

Time
Date
Outside temperature
Memo (hourly alarm)

The 13 button OBC has the following functions:

Average Speed
Consumption
User selectable speed limit
Remaining range on fuel
Stopwatch timer (for measuring those 0-60 times)
Code function

HR-DATE

Tells both the time and date. If the display is showing incorrect units (e.g. 24 hour clock or reads "UHR"), read the paragraph above to set it. To set the time, press the changeover contact and use the 1000/100 buttons to set the hour and the 10/1 buttons to correct the minutes. Press the changeover contact button again to set. A dot will appear between the hours and minutes to indicate that the clock in running. To set the date, press HR-DATE again and repeat the process. The OBC does not take leap years or daylight savings into consideration.

AVG MPH

Displays the current average speed. Press SET-RES anytime to reset the calculation.

M MPH

Works as a speed limit warning. To set, press M MPH once, then using the 100/10/1 buttons, enter the maximum speed you desire, then press M MPH again to set. If the entered speed limit is exceeded, then the LED will flash and the door gong will sound as a warning. To cancel the feature, press M MPH so the red light is no longer illuminated.

AVG MPG

Displays the current average fuel consumption. Press SET-RES anytime to reset the calculation.

RANGE

Displays the estimated distance until the fuel tank is empty. When the range falls below 9 miles (13 km), it will flash to alert the driver to refuel the vehicle. A "+" sign before the display means there is a greater range than indicated as a result of overfilling the gas tank. The OBC does not calculate the addition of fuel unless at least 1.3 US gallons (5 liters) of fuel is added.

TIMER

Works as a stopwatch to measure times during travel, standstill, and parking. The display shows the running time or the time at which the timer was last stopped. Press SET-RES to start the timer and again to stop it. The maximum time it can measure is 99 hours and 59 minutes.

TEMP

Displays exterior temperature. If the temperature falls below 37 degrees F (3 degrees C), the door gong sounds to alert the driver of possible icy road conditions and the display will flash for 8 seconds. The gong will sound again when the temperature rises above 43 degrees F (6 degrees C).

CODE

Works as a vehicle immobilizer for anti-theft protection. It requires the entering of a code to start the car. If an improper code is entered (or none at all) the starter motor will turn but the engine will not start. If three incorrect codes are entered in succession, or if three attempts are made to start the engine, the horn will sound for 30 seconds. The code must be entered and set at ignition position 1. To set the CODE feature for the first time, turn the ignition to 1 and press CODE. Using the 1000/100/10/1 buttons, enter any number between 0000 and 9999. (If you make a mistake, turn the ignition to position 2 to cancel.) REMEMBER THE NUMBER! Then turn the ignition to 0 to store the code and activate the system. To start the car or to cancel the feature, turn the ignition to either 1 or 2 and input the correct code. The feature will then be cancelled by starting the engine or by pressing SET-RES; if neither of the two are done then the code will be retained in memory.

SET-RES

Used to reset AVG MPH and AVG MPG and to start/stop the stopwatch (TIMER). If the CODE feature is used then the actual time will appear when the correct code is entered and SET-RES is pressed.

REMAINING FUEL

Simultaneously press the 1000 and the 1 button to get remaining fuel in litres (the car needs to be running).

Common Problems

Setting Units

If the power supply has been disconnected, then the OBC resets to German and metric units. To set it to the appropriate units of measurement, press AVG MPH. Then, using a ballpoint pen, press the changeover contact button once (the little button located on the lower right corner). Press AVG MPH once more for American units, twice for Imperial (M/G), and thrice for metric (L/100). Press the changeover contact button again to set.

Inaccurate Fuel Range

The range function can be wildly optimistic at times, and needs to be recalibrated to give more realistic readings. To do this, brim the fuel tank and then remove the plastic grommet from the bottom left of the obc. Press the 1000 and 1 buttons at the same time to give a reading of how much fuel is in the tank and then turn the screw behind the grommet until it reads whatever capacity your tank is when full.

AAAA/PPPP

These are fault codes, and are usually generated if the battery has been disconnected for a length of time. To reset your OBC, switch on your car's ignition position, push the CODE button and use a pen to press the small button in the hole in the right bottom of the OBC.

Faulty Bulb

After twenty years, it should be no surprise that the bulb that illuminates the OBC could blow, and require replacing. Unfortunately, the OBC the bulb is soldered to a circuit board, and BMW replacement prices are constantly rising.

However, it is possible to de-solder the bulb from its circuit board, and replace it with a standard 5V unit. Learn how to replace the OBC bulbs.

@@ Line 1: / Line 1: @@
-== Introduction ==
+The On Board Computer (OBC) was a digital meter unit offered by BMW. It provided live data such as time, average speed and fuel range, and was mounted in the [[Interior#Centre_Console|centre console]]. If you want to add one to your [[E30]], learn more about [[Retrofitting_OBC|installing the OBC]].
-After a great deal of interest in members needing to know about retro fitting an OBC, I have decided to write an article to try and save having to repeat myself.
+__TOC__
-The 13 button OBC was optional on 6 cylinder cars in the UK and [[:Category:E30_Sports_Models|SE models]] were always fitted with it from the factory.  When I was searching for a car, I really wanted one with the OBC factory fitted as I’d been told that it was incredibly difficult to retro-fit one, however, I ended up getting a car without.  I then did some investigation into how these are actually fitted and found out that it’s not as difficult to do as I’d previously thought.
+=Types=
-For you guys who own 318’s where the OBC was not an option, a [[325i]] OBC with an [[M10]] [[318]] instrument cluster has been tested and all the readings seemed accurate. If your car has an OBC relay and an ambient temperature sensor, then I believe this conversion will work for you.
-== Functions of the OBC ==
+==6-button==
-The 13 button OBC has the following functions:
+The 6-button OBC unit was a standard upgrade from the analogue clock that is present in the E30 central column. This 6-button unit provides basic Time and Date functions, as well as setting reminders such as hourly alarms; a feature designed by BMW to remind the driver to turn on his radio for the news. How thoughtful.
+==13-button==
+The 13 button OBC was optional on 6 cylinder cars in the UK, and standard on all [[:Category:E30_Sports_Models|SE models]]. They continue to be an extremely desirable extra, and are a more popular retrofit due to their larger range of features compared to the 6-button unit.
+=Parts=
+The simplest OBC unit is a self-contained computer that requires only a wiring loom to the [[Instruments#Dash_Cluster|dash cluster]], in order to read information such as speed. A standard addition is a secondary loom to control the car horn, and to provide access to an external temperature sensor. A gong was also featured to provide audible alerts. For the more advanced OBC a control relay is required, mounted above the main vehicle [[ECU]], and an extra control stalk was available, to operate the OBC from the steering column.
+=Operation=
+For a full explanation of the OBC and how it's used, we've [[OBC_Instruction_Book|uploaded the instruction book]] for you.
+=Functions=
+The [[#6-button|6 button]] OBC has the following functions:
 * Time
 * Date
+* Outside temperature
+* Memo (hourly alarm)
+The [[#13-button|13 button]] OBC has the following functions:
 * Average Speed
 * Consumption
@@ Line 17: / Line 37: @@
 * Remaining range on fuel
 * Stopwatch timer (for measuring those 0-60 times)
-* Outside temperature
 * Code function
-== Parts==
-You will need the following parts in order to retro fit your OBC, I will start off with the essential parts, the bare minimum to get it working and then I will list the optional parts.  I will also list their locations so that if you are removing the OBC from a scrap car, you will know where to look for the bits:
-'''Essentials'''
-* Main OBC unit (Mounted in the dash above the heater controls)
-* Wiring loom (Runs from the rear of the instrument cluster to all ancillaries)
-* Relay control module (Above ECU mounting plate)
-'''Optional'''
-* Outside temperature sensor (In nearside brake duct)
-* OBC Horn (Just above the temp sensor)
-* Temp sensor\horn wiring loom (Follow back from the temp sensor and joins to main loom shortly after entering the bulkhead)
-* Audible gong (Mounted in trim panel above foot pedals)
-* Remote indicator stalk (If you don’t know where this is, give up now)
-* Tools required to do the job
-== Fitting ==
-Before you begin to think about fitting the OBC, you will need to remove certain things from the car in order for you to access certain areas.
-First remove your [[E#)_ICE|stereo]], you will need to use the relevant release keys depending on the make of the unit.
-Next remove the lower trim panel above the foot pedals
-Now you will need to undo the glove box, unclip the 2 pins that hold it up and allow it to rest in the foot well.  Now undo the single cross-head screw that holds the upper trim in place, this is located next to the latch.  There are also a couple of plastic screws which require a 1\4 turn to release.  Now remove the panel.
-Finally you will need to remove the [[Instruments#Dash_Cluster|instrument cluster]].  Learn more about [[Instrument_Cluster_Replacement|removing your instrument cluster]].
-Now you should have sufficient access to start fitting the OBC. Start off by threading the wiring loom through the dash and guide each plug\connector to the approximate location (as shown previously) ready for fitting.  You may wish to clip the loom in with the main wiring loom, this is entirely up to you and will make it look more factory should you or anyone else in the future, decide to remove parts of the dash again.
+==HR-DATE==
+Tells both the time and date. If the display is showing incorrect units (e.g. 24 hour clock or reads "UHR"), read the paragraph above to set it. To set the time, press the changeover contact and use the 1000/100 buttons to set the hour and the 10/1 buttons to correct the minutes. Press the changeover contact button again to set. A dot will appear between the hours and minutes to indicate that the clock in running. To set the date, press HR-DATE again and repeat the process. The OBC does not take leap years or daylight savings into consideration.
-Now that your loom is in place, you can start connecting the parts to it.  I would fit the actual OBC unit first, this can be quite fiddly and I must stress… do NOT drop the screws that hold it it, you will never find them again if you do!!!
+==AVG MPH==
+Displays the current average speed. Press SET-RES anytime to reset the calculation.
-You will need to release the heater panel in order to make life easier when fitting the unit.  Pop out the rear heater switch and hazard light switch and whatever other switches or blanking plates you have there (should be 4 in total).  Behind 2 of these you will see a screw, undo these 2 screws taking care not to drop them.
+==M MPH==
+Works as a speed limit warning. To set, press M MPH once, then using the 100/10/1 buttons, enter the maximum speed you desire, then press M MPH again to set. If the entered speed limit is exceeded, then the LED will flash and the door gong will sound as a warning. To cancel the feature, press M MPH so the red light is no longer illuminated.
-You now need to make use of the stubby cross-head screw driver, beneath the heater panel if you stick you fingers underneath you will feel another couple of screws, undo these and the heater panel should come loose.
+==AVG MPG==
+Displays the current average fuel consumption. Press SET-RES anytime to reset the calculation.
-There are 4 screws fixing the OBC in place, you will need to use the stubby screw driver again here to do up the 4 screws, I put my hand through the hole for the stereo and did them up this way.  Ensure that you fix the green plug to the unit before securing it as it will be difficult to plug it in once the OBC is in place.
+==RANGE==
+Displays the estimated distance until the fuel tank is empty. When the range falls below 9 miles (13 km), it will flash to alert the driver to refuel the vehicle. A "+" sign before the display means there is a greater range than indicated as a result of overfilling the gas tank. The OBC does not calculate the addition of fuel unless at least 1.3 US gallons (5 liters) of fuel is added.
-Refit the heater panel in reverse of removal.
+==TIMER==
+Works as a stopwatch to measure times during travel, standstill, and parking. The display shows the running time or the time at which the timer was last stopped. Press SET-RES to start the timer and again to stop it. The maximum time it can measure is 99 hours and 59 minutes.
-I would now fit the relay control module.  You will need to undo the four 10mm bolts that hold the [[ECU]] in place and then remove the plate above the ECU.  The relay control module is held in place on top of this plate by two large cross-head screws.  Fix the relay control module and refit the plate and ECU, plug the loom into the module.
+==TEMP==
+Displays exterior temperature. If the temperature falls below 37 degrees F (3 degrees C), the door gong sounds to alert the driver of possible icy road conditions and the display will flash for 8 seconds. The gong will sound again when the temperature rises above 43 degrees F (6 degrees C).
-At this point I would test to make sure that the computer is working, plug the yellow connector into the back of the instrument panel and turn on the ignition to make sure that the computer lights up, it should light up orange and flash the letters UHR.  If all is well at this point then continue.
+==CODE==
+Works as a vehicle immobilizer for anti-theft protection. It requires the entering of a code to start the car. If an improper code is entered (or none at all) the starter motor will turn but the engine will not start. If three incorrect codes are entered in succession, or if three attempts are made to start the engine, the horn will sound for 30 seconds. The code must be entered and set at ignition position 1.
+To set the CODE feature for the first time, turn the ignition to 1 and press CODE. Using the 1000/100/10/1 buttons, enter any number between 0000 and 9999. (If you make a mistake, turn the ignition to position 2 to cancel.) REMEMBER THE NUMBER! Then turn the ignition to 0 to store the code and activate the system. To start the car or to cancel the feature, turn the ignition to either 1 or 2 and input the correct code. The feature will then be cancelled by starting the engine or by pressing SET-RES; if neither of the two are done then the code will be retained in memory.
-Next I will explain how to fix the indicator stalk, this is fairly straight forward.  Remove the lower steering column by removing the retaining screws and it should drop down.  Next unplug the existing indicator stalk from the main loom and then undo the 2 retaining screws which hold the stalk in place.
+==SET-RES==
+Used to reset AVG MPH and AVG MPG and to start/stop the stopwatch (TIMER). If the CODE feature is used then the actual time will appear when the correct code is entered and SET-RES is pressed.
-You will now be able to swap the stalks over and re-assemble the trim.
+==REMAINING FUEL==
-Next you will need to fix the temperature sensor into the left hand brake cooling duct, there should already be a place that it plugs into, you will easily see this.  You will also need to bolt the OBC horn and cover on, this goes up above where the fog light would be situated, it’s hard to explain exactly but you will know when you see it especially if you removed the computer from another car yourself.
+Simultaneously press the 1000 and the 1 button to get remaining fuel in litres (the car needs to be running).
-Plug the temperature sensor\horn wiring loom into both the sensor and horn, feed it back along the side of the engine bay clipping it in with the rest of the wiring.  You will see a rubber grommet beneath the brake servo, push the end of the loom through the grommet and into the car.
+=Common Problems=
-Now working from inside the car, attach the two looms together behind the glove box.  You will see a main earthing point here which holds several brown wires onto the point with a nut, remove the nut and place the brown PBC earthing wire on the earthing point and secure the nut again.
+==Setting Units==
-You should now be left with 2 loose wires, a singe green one and a red with white tracer.  These wires simply plug into the main control box, there is only one place that each will fit so you shouldn’t have any problems there.
+If the power supply has been disconnected, then the OBC resets to German and metric units. To set it to the appropriate units of measurement, press AVG MPH. Then, using a ballpoint pen, press the changeover contact button once (the little button located on the lower right corner). Press AVG MPH once more for American units, twice for Imperial (M/G), and thrice for metric (L/100). Press the changeover contact button again to set.
-Finally it’s just a case of reassembling the dash and glove box and re-fitting the stereo.
+==Inaccurate Fuel Range==
+The range function can be wildly optimistic at times, and needs to be recalibrated to give more realistic readings. To do this, brim the fuel tank and then remove the plastic grommet from the bottom left of the obc. Press the 1000 and 1 buttons at the same time to give a reading of how much fuel is in the tank and then turn the screw behind the grommet until it reads whatever capacity your tank is when full.
-Article written by E30Adam and copyright to E30zone, must not be duplicated without written permission.
+==AAAA/PPPP==
+These are fault codes, and are usually generated if the battery has been disconnected for a length of time. To reset your OBC, switch on your car's ignition position, push the CODE button and use a pen to press the small button in the hole in the right bottom of the OBC.
+==Faulty Bulb==
+After twenty years, it should be no surprise that the bulb that illuminates the OBC could blow, and require replacing. Unfortunately, the OBC the bulb is soldered to a circuit board, and BMW replacement prices are constantly rising.
-'''For a fitting guide for lhd cars
+However, it is possible to de-solder the bulb from its circuit board, and replace it with a standard 5V unit. Learn how to [[OBC_Bulb_Replacement|replace the OBC bulbs]].
-'''
-http://www.r3vlimited.com/tech/obc/obc.htm
 [[Category: Technical]]
 [[Category: Electrics]]
 [[Category: Interior]]

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