DIAG Test Codes on dash display

AW8 · #1 05-02-2007, 02:24 PM

Car goes in for it's first Inspection 2, brake fluid and coolant changes at UK BMW dealer tomorrow.

Within the last couple of days the "ENGINE" WARNING LAMP has illuminated despite me being on yellow service lamp only, (red not displayed yet). Manual states this indicates deterioration of exhaust emisison control values requiring examination by dealer. Don't know if it's a faulty sensor ( o2- MAF ???) No doubt your diagnostic test within the Insp 2 will explain matters. I do not currently have and OBDII scanner/reader and haven't had chance to pull any codes but the car drives ok with no recent changes to acceptable combined mpg of 20.4 (official govt fig = 20.3).

Now the intersting bit for which I would appreciate any knowedgable comments. I know how to access and unlock all the dash displayed test info having read how to do it on here and elsewhere. ( Held in right hand push button under main clocks then used left knob to getr to Test 14 which I had unlocked by adding up all individual numbers in VIN and using this as unlock code). Access of Test NR-14 displayed the following results :

DIAG 1 BF 88005
DIAG 2 8D 90000
DIAG 3 3F 88000
DIAG 4 90 84000
DIAG 5 C7 81000

These codes mean nothing to me & I believe they are not recognised generic OBDII codes, (they don't start with a P for powertrain). I am not daft and have not and would not reset anything!

Just wonderd if anyone had a list of these dash displayed codes and source where they can be cross referenced to official OBDII codes.

If the car stays, (hopefully), in my hands for a while I may later purchase a suitable gizzmo to pull the codes via OBD socket. I just thought it would be excellent if by some chance someone knew how to decipher "DIAG code readings" in test 14. Dealer seemed to have no idea what the codes or info meant.

BTW I have my own copy of info from http://www.ideaphile.com/bmw/540-obc.html but no real info re deciphering Test 14 info.

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AW8 · #2 05-05-2007, 03:37 PM

Update- dealer stated only historic fault code relating to car found was o2 sensor but the fault has cleared. I reckon this may have been down to me not tightening fuel cap properly a week or so ago - a known cause of this light activating according to what I have read on here. Here's hoping.

I would still be interested if any BMW techs or X5 tech gurus can explain the DIAG figures/data in test 14 in detail...........................Comments anyone ?

AW8 · #3 08-30-2007, 09:27 AM

Bump - I don't have any fault codes now but would still be really interested if anyone is able to clarify this matter.

Does anyone know how to interpret or translate these codes which obviously mean something and appear to be info re diagnostic faults ?

AW8 · #4 09-02-2007, 08:37 PM

edited bump

AW8 · #5 09-11-2007, 05:09 PM

Update !

Okay guys I believe these are BMW HEX codes.

Does anyone agree or disagree ?

“WARNING IF YOU ACCESS OR TRY TO ACCESS ANY OF THE HIDDEN 21 TESTS YOU MAY CAUSE A CHAIN OF EVENTS THAT MAY RESULT IN COSTLY DAMAGE OR EVEN EXPENSIVE SYSTEM OR CAR FAILURE ”

AW8 · #6 09-21-2007, 03:46 AM

I can't believe that nobody on here knows more than me. Is there anybody out there ?

AW8 · #7 10-14-2007, 01:32 PM

I seem to be talking to myself here but some searching caused me to find this link http://www.bmwmotorsports.org/BMW_docs/OBDproc.pdf

This seems to be a definitive list of hex codes for various OBD2 complaint BMW engines including 4.4i M62.

Go to Page 16 of link for pdf charts and decimalised index

Column 5 heading is marked fcdec (fault code decimal ?) and hex.

The fcdec is a sequential number index starting at 1.

Below the fcdec is the heading hex which I believe to be the hex code.

All the readings I had displayed ended 000 except DIAG1 which ended 005.

All the codes in the listed in the pdf are 2 character/figure length.

I am guessing that 00 means NO Faults Present, (dealer only found one code and that was for precat bank 2 o2 sensor).

I cannot ascertain what the earlier letters and numbers mean but would guess these are probably providing relevant specific "cycle" or time/scan info from OBD2.

Hex Code 05 on M62 (columb M62 is checked on pdf) relates to " precat o2 sensor" as diagnosed by dealer.

The 05 data at end of my DIAG1 is the only numerical code reading for last 3 varaibales and threfore only fault code code displayed if I ignore those ending 000.

I am now threfore of the belief that test NR14 can be used to find hex and that using this list means I can refer it to a specific fault/component on my car.

The chart on the link also indicates how many cycles are required before the check engine "MIL" lamp will automatically go out after problem rectified or new component fitted. These vary depending on componet effected.

Hope this helps someone - if anyone knows more feel free to post your views.