He went on Alldata and another program and neither had any info for any codes over 250. We suspect the 251 could be a bad gas cap, but the other we don't know. He reset it and as soon as I ran with it once and turned the car off/on it came right back.
Went online and found the following:
Evaporative Emission Control – On Board Diagnostic System
E36 – BMW 318i and BMW Z3 with M44 produced from January 1997
E36 – BMW 328i produced from October 1995
E36 – BMW M3 produced from March 1996
E38 – BMW 740i/iL and BMW 750iL produced from May 1997
The ‘check engine lamp is illuminated, and one or more of the following faults are set in the Engine Control Module (DME):
-In the M52 Engine the complaints include the tank venting system, minor leak (Code 251), Tank ventilation (Code 252), Shut-off valve, activated charcoal filter, jammed shut (Code 253) or Tank venting system, major leak (Code 254).
-In the M44, M62 or M73 Engine the complaints include the tank venting system, major leak (Code 94), Shut –off valve, activated charcoal filter, jammed shut (Code 96) or Tank venting system, minor leak (Code 97).
The check engine lamp will only be illuminated if the fault is present during two consecutive drive cycles. To complete a check of these systems the vehicle needs to run in a way that allows these functions to work fully. Any attempt to duplicate the specific driving condition will be unsuccessful, thus it is recommended that the test modules through BMW specific test tools are utilized. One driving cycle includes engine start up - drive - engine shutoff and will test the:
-Evaporative system – component functional check
-Evaporative system leak detection
-Tank venting/shutoff valve operation
-Monitoring catalytic converter efficiency
-Secondary air induction operation
If a fault occurs due to a major leak or a minor leak being present then check if the fuel filler cap has been installed correctly. This can be easily detected if the cap can be easily pulled off. To clear the fault properly install the cap, printout the fault information, clear the fault, select service functions, select DME system test, select 3- Leakage diagnosis, tank venting system.
If the fault returns the system needs to be checked for further leaks using the Evaporative System Leak Test Pool with an A/C leak detector.
If NO leak is detected the following component checks need to be carried out:
-Check the fuel filler gasket has not been damaged.
-Check operation of purge valve.
-Check purge valve using a hand held vacuum pump to check the valve can hold a vacuum.
-Check the o-ring is properly installed.
-Check for any broken hose fittings in the expansion tank.
-Check the operation of the shut-off valve.
-Check the shut-off valve has been correctly installed into the charcoal canister.
-Check routing of hose going to the fuel tank pressure sensor. If the hose is pinched it should be rerouted or shortened.
If the fault occurs through the shut-off valve the following must be checked:
-The routing of the hose going to the fuel tank pressure sensor. If the hose is pinched it should be rerouted or shortened.
-The operation of the Shut-off Valve, Purge Valve and Fuel Tank Pressure Sensor should be tested.
-Remove the shut-off valve from the charcoal canister and look for obstructions which do not allow the valve to shut correctly.
Once i had the same problem,i went to dealership to meny mechanics and nothing,once an old guy,he was driving an M3 said: "Try to close yor tank cup" after pumping gas when you close it,you should hear a clic,if you heard that clic it should be fine! I did and it didn't apear anymore! Good luck!
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