BMW OBC Coding Plug - Peter D
BMW E34 On-Board Computer (OBC) Eprom Coding Plug Problem !

I have a 1995 BMW 520SEi 24v.

I have recently Retro-fitted an On-Board Computer (OBC) into my vehicle (which does not have Check Control in the Instrument Cluster).

The problem i have is after i fitted the OBC i had to disconnect the battery for another job and on reconnection of the battery the OBC now displays "PPPP" which means the OBC doesn't recognise what vehicle it's in.

I know this is an error with the Eprom Coding Plug in the back of the OBC (which store's the vehicle's details) which has probably been erased maybe due to a power spike on reconnection of the battery.

The OBC Type is a Type IV.

There are TWO types of OBC IV, one is for a 518, 520 and the second is for a 525 upwards.

The OBC for the 518, 520 has the Green Coding Plug in the back of the OBC instead of being in Intrument Cluster.

Does anyone know how to re-program the Eprom Coding Plug IC with my vehicle's details ?

Thanks for any Help !!
Peter, you may want to try this website, if you havent already.

Can you tell me what functionality the obc has actually provided you with?
BMW OBC Coding Plug - Peter D
ALL Function's will work on the OBC once the Retro-Fit is complete (OBC, Coding Plug, Gong & Temp Sensor).
I have replaced my Analogue Clock with a Full OBC Type IV (approx £50 from, installed the GONG (approx £10 from under the driver footwell and am currently sourcing the Temp Sensor behind the Front Bumper. The whole wiring loom is already present in all 518's and 520's, so it's just a case of plugging everything in (except the back of the OBC is deeper than the analogue clock but it's easy to modify the bracket to make it fit).
As the 518, 520 does not have Check Control in the Instrument Cluster, the OBC requires a Coding Plug to be soldered into the back of it. (approx £22 from BMW).
A very brief description on how to Retrofit the OBC can be found here :
These two PDF files detail exactly how to do it, only snag is they are in German but there are loads of pictures and it can be easily translated using Yahoo's Babelfish.

How to Fit OBC, Gong & Temp Sensor :
How to Fit Coding Plug to OBC :

The OBC (On Board Computer) gives information for the time and date, fuel consumption, speed limit warning, outside temperature, stop watch, distance to go, and average speed. Here's a brief description on each of the functions that the obc can do :

km/°C miles/°F This switches the readings for metric to imperial.
1000,100,10,1 Used to enter figures S/R Set/Reset, used after entering some figures, or to start or stop the timer.
HR/DATE This gives the time and date.
CONSUM This gives the average fuel consumption of the car, press the button a second time, and gives a second consumption reading. I use the first for tank to tankful average, the second for a yearly average.
RANGE This shows how many miles are left before running out of fuel. depending how much fuel is in the tank and speed.
SPEED This shows the average speed the car is travelling at, over the length of your journey.
TEMP This shows the outside temperature. Gong will sound for ICE Warning.
TIMER This facility can be used to turn on the fan to cool the car before you get into it, or if you have the option to turn on the heating to warm the car on a cold mornings.
ARR This feature is used to set the time of when you expect to arrive at your destination and sounds the gong when time is reached.
DIST This feature, you input the journey distance, and it counts down the miles.
LIMIT This feature allows you to set a speed limit, and sounding the gong when you have reached it. Useful to stop getting those speeding tickets on the motorway :-) .
CODE This allows you to enter a 4 digit code to immobilise the car. Only when you have put in the correct code are you allowed to start the car, no code input will sound the anti theft device.

There are also 20 additional HIDDEN TEST functions available on the OBC IV in the TEST Menu :
Matrix display activation of LEDs
AVG fuel consump. (car must be moving) liters per 100/Km
AVG momentary fuel consump. liters per hour
Fuel consump. for range AVG last 50 Km (dampened)
Fuel consump. for range determined (not dampened)
Present fuel amount liters (not dampened)
Present fuel amount liters (dampened)
Road speed from inst. cluster K.P.H.
Battery voltage Term. 15
Sets reserve amount E-34 only
Programming language E-34 only
AVG speed for ARR time K.P.H.
Arrival time undampened
MFG date of ROM
Fault memory for MFG purposes
Check of inputs and out puts
All data for OBC IV
Horn sound for code alarm
Lock or Unlock
Correction factor

WOW, thanks for the detailed reply Peter. I have a 525 tds and I am contemplating doing the same as you.


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