Relevant Roundel references:
The Roundel is the monthly
publication of the BMW Car Club of America BMW CCA .
Jan 1992, Nov 1991,
Dec 1989, May 1988 -- Resetting the service indicator lights
Nov 1991 -- Replacing
the Nicads.
Some generic marketing-speak about the Service Interval Indicator SII can be found at the BMWNA site.
The BMW service indicator lights are generally believed to be totally useless for indicating when you should service the car. The cheapest, ugliest solution for turning off the service light is to cover them up with black tape. If you want to be more adventurous, you can remove the instrument cluster and cut the wire going to the lights. True motorheads will read on though.
The service indicator lights are reset through a pin in the diagnostic connector located in the engine compartment. There are 2 types of diagnostic connectors used on BMWs. One is a 15 pin connector used on 1987 and earlier cars, the other is a 20 pin connector used on 1987-on cars. In what follows the 15 pin connector is referred to as the early type and the 20 pin as the late type. Resetting the service indicator lights is described below. The most common problem with resetting the service lights is bad NiCad batteries in the instrument cluster. The batteries seem to fail pretty consistently after 4 years. The symptoms of this are:
The service indicator lights are reset by connecting pin 7 to pin 19(ground). The proper way to do this is to have the ignition off and place a jumper wire between pins 7 and 19 (make sure you get the right pins - see diagram). Then turn the ignition switch to position 2 (run, NOT start), when the service light goes out, turn the ignition off. This should take a few seconds for an oil reset, 8-10 seconds for an inspection reset. All green lights should come on when the service light goes out. The difference between resetting the oil service light and the inspection light is in the length of time you have the jumper in place with the ignition on. This means that if you are resetting the oil service light, you should turn off the ignition immediately after the light goes out. If you leave the jumper in too long with the ignition on, you will perform an inspection reset as well and the next service indicator will come up as an oil service rather than an inspection.
The service light reset tools that I have seen connect to 3 pins of the diagnostic connector: pin 7,14 and 19. The connection to 14 is to power the tool. The less sophisticated tool has only one switch that connects pin 7 to 19. While those pins are tied together a red LED blinks to measure time. You count blinks and manually turn off the tool after the appropriate number of counts for oil or inspection reset. The more sophisticated tool has two switches, one for oil reset, one for inspection. It must have a built in timer that jumps pin 7 to 19 for the correct time.
Notes on the latest model cars (93 on?):
(can someone please verify this?) It is claimed that the above procedure doesnt quite work
on the most recent model year cars. Instead of waiting for the lights to
go out, you have to disconnect the jumper between 7 and 19 while the ignition
is still on.
The procedure is the same as above, but you jumper pin 7 (the service indicator pin) to pin 1 (the ground pin). See the diagram below.
*******
**** ****
*** (10) ***
** (9) (11) ***
* *
* (2) *
* (8) (3) *
* *
* (7) *
* (1) *
* (4) *
* *
* (6) *
* (15) (5) *
* *
** (14) (12) ***
*** (13) ***
**** ****
*******
No. Terminal Designation
1 31 Ground
2 - -
3 - -
4 FT Temperature gauge
5 L Engin M10B18 Interfrator output for CO adjustment
Engin M30B34 Oxygen Sensor signal
6 A Diagnosis lead for SRS
7 SI Service indicator
8 P+ Position sender
9 S Shielding
10 P- Position sender
11 50 Starting pulse for starter
12 61 Alternator charge indicator
13 1 Ignition signal
14 30 battery +
15 15 Power supply for ignition
** ***
**** ***** ****
*** (1) ***
** (12) (2) ***
* *
* (11) (20) (13) (3) *
* *
* (10) (19) (14) (4) *
* *
* (15) *
* (9) (18) (5) *
* (16) *
* (17) *
** (8) (6) **
** ***
*** (7) ***
**** ****
*******
From the BMW NA 1989 Electrical
Troubleshooting Manual for the 325i/iS:
| Diagnostic Plug Connections | |||
|---|---|---|---|
| Pin | Wire Size | Wire Color | Circuit and Component Connected |
| 1 | 1 | BK | Ignition Coil, Motronic Control Unit |
| 6 | 0.5 | WT/GN | SRS Connector (Not Used) |
| 7 | 0.5 | WT/GN | Service Interval Indicator, Service Interval Processor(Reset) |
| 11 | 2.5 | BK/YL | Starter, Start Signal(50) |
| 12 | 0.75 | BU | Charge, Alternator(D+) |
| 14 | 2.5 | RD | Battery |
| 15 | 0.5 | WT/YL | Motronic Control Unit(RXD) |
| 16 | 1.5 | GN/WT | Oxygen Sensor |
| 18 | 0.5 | GN/BU | Motronic Control Unit (Programming Voltage) |
| 19 | 1.5BR | BR | Ground Distribution(G103) |
| 20 | 0.5 | WT/VI | Motronic Control Unit(TXD) |
The cap on the diagnostic connector is actually an electrical connector that shorts together the following pins:
From: prreitz@amp.com (Paul R. Reitz)
Date: Wed, 11 Oct 1995 08:59:20 -0400
Subject: Resetting the E30 SI indicator
>Soo does anyone know what the electronics around all those pins looks like,
>or has anyone ever done any measurements? I'm guessing (again) that in a
>harsh automotive environment the input resistance to any electronics could
>range anywhere from 1k to 50k ohms in order to protect the inputs from
>zaps etc.
>
>>For those of us who like to live dangerously (but but refuse to jump
>in first), any Takers?!! who can resist the Resistor?!!
Frank et al,
I don't know what the electronics look like, but agree that it's safer to use
a series resistor when "shorting" the SI reset pins. The electronics
probably vary from one model to another (ours is a '91 E30), but based on the
test I ran, I'd suggest 1 k ohm series resistance.
After reading the faq and consulting the ETM for this car, I used a handy-dandy (unusual and expensive) 4 decade ganged pushbutton variable resistor in series with the wire from the reset pin to ground. Obviously, any good variable resistor would have worked, but I wanted to get a better idea of exactly what kind of resistance to ground was required. The resistor was set to > 100k ohms at first, and was incrementally reduced after turning on the ignition. It was down to about 1 k ohm when the lights turned green. However, one important caveat is that I didn't count to 3 or 8 or 20 or whatever, so maybe it would have still reset at a higher resistance if I waited longer.
It makes sense that electronic I/O would be at relatively low impedance to avoid stray pickup from other pulsed electronics in the engine compartment. Anyone with specific knowledge of these electronics willing to step up to the plate?
- --Paul Reitz
BMW CCA #1167
As we mentioned above, the most common problem with resetting the service lights is bad NiCad batteries in the instrument cluster. The batteries provide a 3-volt power supply to the service indicator circuit while the car is off, and they seem to fail pretty consistently after 4 years. If you are having problems resetting the indicator, you probably need to replace the batteries.
Update 11/30/93: BMWNA is now stocking a replacement SI board with lithium batteries which should last much longer. They are available for about $160.00 US. Here's a copy of Rick Kjeldsen's instructions on how to replace the Nicad batteries. You might want to just run 3 wires from the instrument cluster to a convenient location to mount the batteries so in 4 years when it happens again you can easily replace the batteries. You need to use 3 wires because the center tap of the 2 batteries is used on the SI board as well as the 2 ends. Note: The SI board also feeds the tach and "fuel economy" gauge. Trouble with those two gauges is often related to screwed-up SI boards.
Date: Thu, 27 Aug 92 12:56:41 EDT
From: "Rick Kjeldsen"
To: bmw@balltown.cma.com
Subject: Changing service indicator light batteries - LONG
I've gotten a bunch of requests for this, so I'll post it.
This a quick summary of how to change the batteries for the service interval processor on E30 325's. I don't know how much is different with the 5/7 series, but I have a feeling is basically the same. You can also find an article on this is the November '91 Roundel, but what follows is from my experience.
The processor is on a board mounted in the instrument cluster. The batteries are soldered to the board, and a dealer wants ~$200 because he replaces the whole thing.
To replace the batteries, first remove the instrument cluster from the dash. On the E30, that means first removing the plastic trim below the cluster (at the bottom of the dash just above the steering column). That exposes the bottom screws for a trim piece that wraps around the cluster (couple of screws on the bottom, couple up under the &qout;eyelid") That, in turn, exposes the screws for the cluster itself. There are two (I think) on the bottom, and two on black tabs that stick forward from the top of the cluster. Remove them and pull the cluster forward and out. Take a good look before you unplug the wiring, there are 4 or 5 plugs you have to take out. Once you've seen it, you won't have trouble getting it back correctly, they are color and shape coded pretty well.
Now set the cluster face down on a table (careful not to scratch the plastic face!) On the back, there are several (about 8-10) screws, most around the edge, with one or two in the middle. Take them out, and the whole back will come off, and you will be able to see the board (It's the only board in there, along the bottom and goes most of the way from one end to the other). Remove the board.. to do that, you have to remove two things. One is the engine code plug which plugs in to the board from the opposite side (the outside of the instrument cluster). It is a plastic rectangle about 1"×1"×.5". You have to press a tab to unclip it and pull it out. The other thing holding the board is a plastic piece that is held in by one screw. Take the board out, and you will see the batteries in the middle.
Mine were two NiCad AA cells with something like "Varta 500 RST" on them. These are top of the line NiCads. You can replace them with standard replacements (e.g. Radio Shack AA NiCads), or if you have a good electronics store nearby, order them from Varta. Either one will have the same voltage, so work the same, but the Varta's will have more capacity, so last longer when you pull out the car battery, and perhaps not die as soon either. (The Varta's have 600 mAmp hours capacity vs 450 for the Radio Shack AAs. Both are 1.2V).
A possible source of the nicads is
E.H. Yost & CompanyThe old batteries are held on by tabs that are welded to the battery on one side, and soldered to the board on the other. Remove the solder with a solder-sucker or solder wick (again, see Radio Shack), straighten the pins and remove the batteries. Be sure to remember the polarity of the batteries for when you reinstall them. The original batteries are marked +/-, but the board isn't.
You have to rig up a way to solder the new batteries to the board. You can take the old mounting tabs off the old batteries, and remount them to the new ones, but that is tough. You can buy batteries with mounting tabs, the Varta's may come with them, I'm not sure. The Radio Shack tabs won't mount directly to the board, I cut them to fit. You could also rig up a wire to go from the tab to the board. Anyway, take a look at it. It's pretty easy to figure something out.
One warning, on my board the tabs were soldered to the board at one point on one end of each battery, and at two on the other end. It turns out that on the end with two connections, one of them is just for strength and has no electrical properties. I just soldered to the one, but if you aren't sure which is which by looking at the board, You can solder a small wire between the two holes and just mount the battery to one. My batteries originally had a small amount of glue holding them to the board. When I replaced them, I replaced it with some silicone gasket material to help keep the batteries from vibrating loose.
All that sounds complicated, but it's really not if you have a little soldering experience. The only things you have to be careful of are to not crack the board while you are playing with it (not a big deal, it is pretty rugged) and when you solder, don't create any bridges (shorts) between leads on the board. That's easy if you just don't use too much solder. It's probably a good idea to charge up the batteries before you install them if you can.
Then just reverse the steps to reassemble the cluster and reinstall it in the dash. Don't forget to put back in the engine code plug! You will have to reset the service interval indicator after you are done, of course.
Good luck, if you have any questions about it, send me a note.
rick
These work on OBC II cars:
4 .6TYP
Where the 4 is the car/engine designator, the 6 is the chip firmware.The following is for newer OBC found in E36 cars for example:
To determine if your OBC is eligible .. press 1000 and 10 together ..
you should see TEST NO . or something like that ...
Now, some of the functions are locked out .. I do NOT recommend messing with them and you do so at your own risk ... that said ..
To unlock all functions .. press 1000 and 10 and at the TEST prompt
enter 19 using the keys .. press SET/RES .. you should see LOCK:ON
or something similar ... press the DATE key .. (today you'd see 08.20)
and add the two numbers (day and month) together (today 28)
Now enter the number you just calculated (28) and press SET/RES
TADA .. you have unlocked the secret functions ...
To lock them back up .. press 1000 and 10 then enter 19, SET/RES
now press SET/RES again .. it should show .. LOCK:ON again
In general when I show a test enter it by pressing 1000 and 10 together then enter the number of the test with the numeric keys and press SET/RES to actually execute the test ...
Test numbers for E36 OBC (Note: Joe this should also work for your 535!)
Note: #20 the factor is used to correct the OBC Avg Fuel Consumption figure to reality .. it your OBC is off a bit ... fill UP totally ... run tank down and refill ... calculate your Actual MPG ..
Now enter test 20 get the old Correction Factor ..
NEW CF= OLD CF *(Actual MPG/OBC MPG)
enter the NEW CF using the numeric keys and hit SET/RES to store ..
PLEASE record your OLD CF so that IF you screw up you can always go back to what it was ..
And remember (as Don E. sez ) Your Mileage May Vary ...
This is about a 1988 325is, but many other models are similar.
The backlight for the OBC display is provided by a pair of small incandescent bulbs which are soldered to a small printed circuit board. This board is in a white plastic housing that slides into the right side of the OBC. The bulb assembly cost about $20.00 from the dealer. A resourceful hack mechanic could save 20 bucks by unsoldering the old bulb and soldering in a new one. You probably would have a hard time finding an exact replacement bulb but you could find one close enough.
Added. 11/2/94...
The bulbs are 5 Volt and use about 80 mA. The nearest Radio Shack bulbs are: part number 272-1140, 6 volt. They can be soldered right in the circuit board.
The hard part is getting at the side of the OBC to remove the bulb holder without disassembling the entire center console. You must partially remove the center console panel. The OBC is screwed into the center console panel from the rear with 4 phillips screws. Once the screws are out, it comes out toward the rear (unfortunately!!).
First I removed the radio by loosening the screws that lock it into the center console. These screws are a special 5 sided torx-like screw that require a special tool to remove properly. The tool costs something like $15.00 at the dealer, but you can usually get by with a 2mm hex wrench. The hex wrench might chew up the screw a little bit, but it will still work repeatedly. I did all this with the battery connected so I didn't have to reset codes or reprogram the computer. No electrical connectors have to be removed so there's not much danger of shorting things. The radio has long enough wires that you can pull it out the front and rest it on the ashtray while you do the rest. The Bentley manual really helped on the next step because it showed the location of the screws that hold the center panel. There are 2 #1 Phillips screws at the top, behind the hazard flasher switch, which you have to pull out and leave dangling by the wires, the other behind the dummy plug. The 2 #2 Phillips screws at the bottom are harder to reach--you need a short screwdriver--but they're not that tough. Once the four screws are out you can pull the center console out enough to access the computer. You have to be careful not to snap off plastic edges, slide the panel to the right as you pull to free the lip on the left side. Note that everything (heater controls, radio balance control, etc.) is still connected to the center console. This makes it a little harder to maneuver, but it's a lot less work in the end. [See below for alternate method to removing bottom console screws.] If your wrist is small enough, you can reach in through the radio opening and loosen the 2 Phillips screws that hold the left side of the OBC. You don't need to remove the screws, just loosen them. If you can't fit through the radio opening, you'll have to remove the glove box and side panels to reach the screws from behind. Now with the left side loose you just need to pull the right side of the center panel out about 2 inches until you can access the left side screws. At this point you can see the flush mounted bulb-holder and you realize that this thing was not very well engineered! The center panel cutout blocks access to the slide out bulb-holder. That is why you have to remove the 2 screws holding the left side of the computer. It would have been an easy matter to design a center console that didn't block the bulb. For that matter, it seems it would have been easy to design a computer mount that allowed it to just snap out toward the front or screw out like the radio. The bulb could then be changed in 30 seconds. Back to the 2 left side screws--to really get a screwdriver on these you would have to pull the center panel out at least 4 or 5 inches. It didn't seem like it wanted to be pulled out that far without removing more stuff (like heater controls) so instead I just opened it enough to get a pair of small needle nose vise-grips on the heads of the screws. They aren't in very tight so with a little patience the vise-grips remove the screws.
[Addition from Rick Kjeldsen: The center panel will come completely off the heater if you do the following: Take (pull) off the caps from the 3 heater slider controls. There is a thin plastic cover over the three slider slots that covers 4 screws. It is about the size of a 3x5 card. You have to gently pry it off to avoid damaging it. I found I can pull from one of the slider slots to get it started. That will uncover 4 screws that hold the center panel to the heater core.]
Now the on-board computer can be pushed in from the center panel, the bulb-holder pulled out and the new one slips right in. I checked the old bulbs and sure enough one was burned out (they're in series so this takes out the other one). Just to make sure before I closed everything up, I stuck in the key, turned on the ignition and the correct time of day lit up beautifully!
I just reversed the procedure to get everything back. The biggest problem here was restarting the 2 bottom screws on the center panel. It's impossible to see anything and there isn't enough room even for my small hands. A little patience will get you there though.
[11/5/93 Update: You might be able to get away with this easier method, supplied by Kent Shephard which worked on his M3]
My mechanic showed me how to do this on my M3 today and he said this description is *NOT* the way a flat rate mechanic does it. He works for a dealership and he did my M3 is all of 10 minutes. So folks I'll outline it so the FAQ can be changed. He said all the screws don't need to come out. He said this description is for those obsessed with getting the computer out. So follow along.
* DO NOT REMOVE THE BOTTOM SCREWS *
At this point tilt the top of the console forwad. Don't be scared you won't break it. You will now be able to look on the right side of the computer and see the light module and a single screw. You will need the needle nose pliers to remove that screw. It has fine threads so be patient. Throw screw away. The computer will hold fine with three screws. After the screw is out, pull the module with the needle nose pliers and it will come out. Now slide the new one in and reassemble.
Much of this info came from Jim Conforti at Gateway Tech, 1995.
Early systems (Motronic 1.1 only, I think) flash the fault codes automatically. If the check engine light comes on, leave the key in the On position, but dont start the car. The check engine light will begin to flash the code after about 3 seconds. Each flash is separated by about 1 second. There arent many codes on this system