Hidden instrument cluster tests?

[DrCharles]

When did BMW start putting the hidden tests in the instrument cluster display? My '97 E39 and '98 E38 both have them, but all I can find for the '93 E34 is the self-test mode (hold right button while turning on key, then various numbers show, all lights/pixels illuminate, and the gauge needles sweep).
I was hoping for a real-time coolant temp and battery voltage display as is available on the later model cars.
thanks
Charles

[Matt Z]

The only hidden test the E34 has is the stomp test, google it, but all it will tell you is any stored trouble codes. I would have to guess the test you are hopping for are an OBDII thing so 96+

[shogun]

"I was hoping for a real-time coolant temp and battery voltage display as is available on the later model cars"

that is on the OBC = on board computer, you have to unlock the OBC http://bmwe32.masscom.net/johan/obc_...c_secrets.html

[Hofmeister]

The cluster does have a hidden test. Press the right hand button on while turning the key to accessory. That said its not what you ask for

[DrCharles]

that is on the OBC = on board computer, you have to unlock the OBC http://bmwe32.masscom.net/johan/obc_...c_secrets.html

Thanks shogun, that's exactly what I was looking for I have the OBC-IV.
It does not seem to have a coolant temp readout, but the battery voltage test (and the others) work just fine.

[shogun]

No coolant temp readout on the OBC, that's right. But for thst you have the temperature indicator in the cluster.

The myth about the cluster engine coolant indicator
There were in the past a lot of discussions what is right or wrong when the temperature gauge on the cluster temp indicator is right or left of the 12 o' clock mark.

The truth/fact is:

Temperature indication on the BMW is not linear, they call it 'tableau', basically the indicatior at 12 o'clock can mean everything between roughly 85 +/- 10 degree Celsius. Plus/ minus 1-2 mm to the right or left (deviation cased by the parts installed). I have tested that by myselves with 3 different clusters, changing them within minutes just to see the differences in indication on the gauges.

The analog signal ist processed in the instrument cluster and compared with data in the coding plug. A corresponding signal is sent to the instrument. Five temperature support values are stored in the coding plug.
Exceeding the temperature limit stored in the coding plug will additionally send corresponding warning information to the check control and display it there.

That is written and shown here on page 4 of the instrument cluster check control training reference book http://www.e38.org/e32/BMW_pdfs/INST_info.pdf

What is NOT shown in the English version I found in the German version, here a copy of that page showing the temperature diagram curve in picture 14, and there you see the socalled 'tableau' between 75- approx 100/110 degree Celsius.

http://s71.photobucket.com/user/shog...ml?sort=4&o=18

In the cluster chip the following data are stored (German language)
1. Gesamtwegstrecke km/miles
2.
SI-Stand
SI-Zeit
SI-Grenzwerte
3. Code-Nr. des Codiersteckers
4. Verbrauchskennlinie
5. Wegimpulszahl
6. US/ECE -Ausfuehrung CC III
7. Tank /5 Stuetzpunkte (Liter/Anzeigewerte)
8. Kuehlwasser-Temperaturanzeige/Stuetzpunkte
9. Kuehlwasseruebertemperaturgrenze
10. Grenzgeschwindigkeit (Limit)
11. Ton-Trigger-Ausfuehrung
12. Reserveraum fuer Fahrgestellnummer
13. Zylinderzahl
14. Programmanzeige ausblenden
15. Landessprache CC III
16. Gesamt-KM-Zaehler-Offset
17. Programmkonstanten


This is completely different from my Honda Acty truck which basically shows always too low temperature for my feeling, as I am used to my BMW info. I would interprete it in such way, that BMW wants to have a stable indication for the usually non technically oriented average driver, and only warn when absolutely necessary.

[DrCharles]

Very interesting reading, thanks.
I assume that info is current through '95, although it was published at the end of '89?

As an engineer I prefer not to have a "nanny car" that only tells me what it thinks I should know... Watching the coolant temp in real-time on my E38 and E39 clusters is very interesting. While the temp gauge, of course, stays "tableaued" to a perfect 12:00 position!

[shogun]

Basically that is current thru 1995, there were some changes in the clusters, but that mainly was for us noticable with regards to the 'chip' and self test. There were grey, white, blue backplate clusters, the differences you can see here, the oldest one = grey backplate version did not even have a self test possibility and actually the chip location is in the wire loom to the cluster plug, whereas in the blue and white version they are in the back of the cluster
http://bmwe32.masscom.net/johan/299960/299960.html http://www.exx.se/maintenance/instru...34/index.shtml
Application date..back plate colour Code plug type Size Extra information
start ->02/89 Grey HML 075 2048 bytes No self test or diagnosis via Modic. Stops at 299960. code plug is non-standard
02/89 -> 09/90 White PIC 93C46 1024 bytes Self test + diagnosis via Modic. Code plug is standard EPROM
09/90 -> end Blue PIC 93C56 2048 bytes Self test + diagnosis via Modic. Code plug is standard EPROM

If you really want to have a correct temp gauge, you need to install one separately with a separate gauge, and maybe also with a more accurate temp sensor. The temp sensors for the Motronic and for the cluster gauge for example have different part numbers. I assume the one for the Motronic is more accurate. See www.realoem.com for part numbers