Couple OBC errors... can't rid of them! Help!

[Jon K]

Ok guys, I am going to put the car in the garage for an entire week. Do exhaust, gaskets here and there, fix any electrical issues, detail, etc.

I had BRK LT CIRCUIT... FOREVER... replaced the brake light switch, it won't error until maybe 10 or so minutes (15 perhaps) of driving, then DING. Also, I have WASHER FLUID LOW, even though its full. Another one I get is "PARKING LIGHTS" but I have my turn signals all wired correctly... I do, however, have my side molding lights unplugged. Meaning my bumper trim lights do not light... but I don't think that's an issue with OBC read out. So is my Check Control Module failing or what? Could I switch the module out of my sisters 1995 530i into my 1992 525i or will that blow something up?

[bimmerd00d]

the side trim lights dont trip the parking light sensor, I have the euro side trim too and no error. my washer fluid thing went haywire, got a new sensor and it works fine. brake lt circuit, still get this message with bmw bulbs, and new brake switch.

[Jon K]

the side trim lights dont trip the parking light sensor, I have the euro side trim too and no error. my washer fluid thing went haywire, got a new sensor and it works fine. brake lt circuit, still get this message with bmw bulbs, and new brake switch.



Brandon I cracked open the check control module. Since all this module does is check resistance values across certain circuits, they are naturally just resistors of different ohms. So, I am beginning to think that since resistors don't keep proper resistance "forever," that they are finally starting to become more or less resistive and thus tripping these circuits. Resistors are known to be less efficient when hot (cool temperature is optimum for conductivity) and since my error lights don't trip until the car is warmed up in the engine bay... that could be it.

the PARKING LIGHT error goes on as soon as I turn my headlamps on. I am using HIDs, plugged directly to the low beam connector, but if I had a low-beam error, it'd say LOW BEAM not PARKING LIGHT. So, I am unsure as to what is going on. As asked earlier, does anyone know if I could just swap the check control module from a 1995 530i to my 1992 525i?

[Javier]

done at the LKM, not at the check control. Yes there is a series resistor in LKM responsible to measure the current flow to the lamp circuit, also some lamp check circuits have a high impedance feeding to test when turned off. It is possible you have a LKM high resistor value, thus reporting a short circuit condition to the CCM. Hard to know exactly.

Check control receives info via contacts (connected to ground or not connected), and the data link.

Regarding the exchange. I understand that CCM in 1992 models check a lower number of conditions than in 1995 (an example is opened doors, mine only report driver's door). The LKM I think is also different. The best way to know is to check the ETK part number for both models.

I have no access to ETK right now, but will check later on and post my findings.

Javier

[JD525IA]

I have battled both of these recently.

1. The Brake Light Circuit usually occurs during a drastic temperature change for me, ususally. The easiest thing to do is to change the center light bulb inside the trunk, or at least attempt to clean the contacts. It is the bulb for the light that sits in your back window. Since you have already changed the switch, it is most likely this bulb that is causing your OBC alarm. Aftermarket bulbs tend to crap out quicker than OEM ones, IMHO.

2. I had my Washer Fluid Low message because the sensor had gotten rotated around by about ninety degrees somehow and caused the sensor to float the wrong way. I think the outside connector has to point with the wires going down.

Lots of luck.

JD

[Paul in NZ]

Jon I had trouble with my brake light switch too.When i installed it i pushed the red sleeve in.I had no problems until i had to brake a wee bit harder than normal then my error was back.....When i went to the stealer to buy another switch the service manager told me that the switches are self adjusting and NOT to push the red sleeve in

[Jon K]

Jon I had trouble with my brake light switch too.When i installed it i pushed the red sleeve in.I had no problems until i had to brake a wee bit harder than normal then my error was back.....When i went to the stealer to buy another switch the service manager told me that the switches are self adjusting and NOT to push the red sleeve in


Paul I had left the sleeve out, but still dings.

[Javier]

same per ETK, you can double check with VIN numbers at on line ETK.

If confirmed, you may switch LKM modules to see if brake circuit and parking lights alarm disappear, and CCM for the washer fluid. Guess though that JD suggestion is to be taken seriously, as an open circuit due to corroded contacts will generate an alarm in the CCM, just like coolant level.

I strongly believe that blaming switch brake is a myth, I also replaced mine some years ago, following suggestions, and the car still alarm brake circuit when prolonged braking in heavy traffic. I also believe that when sensing resistor became hot, it goes out of tolerance and report an alarm.

Javier