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:
1. The inspection light comes on.
2. Resetting the light according to the instructions below either doesn't work or works for a short period of time and then the inspection light comes back on.
The fix for this is to replace the batteries as described below.
Jan 1992, Nov 1991, Dec 1989, May 1988 -- Resetting the service indicator lights
Nov 1991 -- Replacing the Nicads.
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!). 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.
Early type connector:
The procedure is the same as above, but you jumper pin 7 (the service indicator pin) to pin 1 (the ground pin).
The early type connector:
Diagnosis plug connections:
The late type connector:
Pin | Wire Size | Wire Color | Circuit and Component Connected |
---|---|---|---|
1 | 1 | BK | Ignition Coil, Motronic Control Unit |
6 | 0.5 | WT/BK | 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:
--pins 18 and 20 to pin 19.
--pin 14 to 15.
Remote Starter: Connecting a remote starter switch to pins 11 and 14 will allow you to start the engine or "bump" it into position for valve adjusting.
Read O2 sensor: ???
Motronic faults: ???
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 2 gauges are often related to screwed-up SI boards.
Date: Thu, 27 Aug 92 12:56:41 EDT
From: "Rick Kjeldsen"
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 "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"x1"x.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
The 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
Use CHARGED NiCads ... some boards will NOT charge up a completely
dead NiCd battery, and you'll think you need a new board ..
PS: I found this out when the local dealer was starting to change
the batteries v. the board .. they told me my instructions didn't
work .. so I came down and found out that *some* SIS bards will
NOT work unless the NiCd batts. are charged *before* install
And *yes* they will now change the batteries, saving their
customers mucho $$$ .. over changing an SIS board
From: prreitz_at_amp.com (Paul R. Reitz)
>Soo does anyone know what the electronics around all those pins looks like,
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
From: JonLindsay_at_aol.com
Here is the routine for replacing the SI Board batteries (and remotely
locating them) on a 633, there are differences on the 5 series because of the
location of the check light panel, but that is a relatively minor difference.
Here goes (first check to see if any of the instrumentation lights are burned
out, now will be the time to note which ones to replace):
Let me know if all works okay or if you need extra, more specific advice.
Updates
Date: Wed, 11 Oct 1995 08:59:20 -0400
Subject: Resetting the E30 SI indicator
>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.
BMW CCA #1167
Date: Thu, 8 Feb 1996 06:48:58 -0500
Subject: 528e s i batteries
Jon Nelson
'84 633CSi
Some generic marketing-speak about the Service Interval Indicator
SII can be found at the BMWNA site.
(return to contents)