E32 ABS sensor testing procedure

[shogun]

I have no experience with scanner

[Annddrriy]

K61 unloader relay when engine is running is grounding pin 2 or staying between 5 and 6. If grounding pin 2 of the K61 then ABS module pin 15 will be OFF.
If ABS module will connect to K61 of pin 6 is relay coil then ABS module pin 15 will be ON and scanner might connect to ABS module. If not then scanner has empty option within ABS module.

[Annddrriy]

Sorry I write that post in ABS section but this could be a problem for ABS also. Bentley indicates that D+ voltage should be battery voltage when ignition switch is in the ON position but engine is OFF. I measure just 1.85 volts. I try to clean B+ junction point those terminals very tight closed and can not unscrew top junction bolt which keeps all big cable together. Did some one cleaned those cables before and how to unscrew junction point bolt ? Thanks !

[E32FAN]

Sorry I write that post in ABS section but this could be a problem for ABS also. Bentley indicates that D+ voltage should be battery voltage when ignition switch is in the ON position but engine is OFF. I measure just 1.85 volts. I try to clean B+ junction point those terminals very tight closed and can not unscrew top junction bolt which keeps all big cable together. Did some one cleaned those cables before and how to unscrew junction point bolt ? Thanks !

D+ will be about 1.85 V with ignition Sw ON while the engine is stopped. This is the exciting current flowing through the A2 Battery Indicator lamps into the alternator field windings.

When the alternator starts spinning, then D+ will rise to the battery voltage. Pages 1230-00 and 01

[shogun]

Sorry I write that post in ABS section but this could be a problem for ABS also. Bentley indicates that D+ voltage should be battery voltage when ignition switch is in the ON position but engine is OFF. I measure just 1.85 volts. I try to clean B+ junction point those terminals very tight closed and can not unscrew top junction bolt which keeps all big cable together.

did you already check the battery ground cable in front of seat base?
http://www.ow.no/gallery2/main.php?g...31e976e55066c0
http://www.ow.no/gallery2/main.php?g...31e976e55066c0

[Annddrriy]

I did already check the battery ground cable in front of the back seat base there is no any corrosion all is in good shape.

[Annddrriy]

D+ will be about 1.85 V with ignition Switch ON while the engine is stopped and all light on dashboard won't turn off until the engine started. Have alternator bad diodes ?
If D+ will have 12v when ignition is on then lights on dashboard turns ON for a few seconds then turns OFF without starting the engine. In some cars alternator doing itself job turns the dashboard all lights OFF before the engine started. It is not draw power from the cluster this way.

[shogun]

I have read about a similar problem on another forum that the cluster always stayed on and the problem were bad alternator diodes. If the alternator has diodes that are shorted it can drain the battery, a diode is a “one way valve” that allows current to flow from the alternator to the battery and when it is shorted it can allow current to flow to the alternator and drain the battery.
https://vehiclefreak.com/bad-alterna...d-how-to-test/
https://axleaddict.com/auto-repair/A...g-System-Tests
I replaced on my alternator the complete rectifier with diodes, not single diodes.

D+ from alternator rectifier cable goes thru this plug next to battery + pole on my 750 http://bmwe32.masscom.net/sean750/Vo...ryTerminal.jpg
http://bmwe32.masscom.net/sean750/Vo...veTerminal.jpg
it has 3 wires, alternator rectifier and 2 for engine oil level sensor

[E32FAN]

D+ will be about 1.85 V with ignition Switch ON while the engine is stopped and all light on dashboard won't turn off until the engine started. Have alternator bad diodes ?

Does your engine start and run?

[Annddrriy]

Yes. Starts and runs with misfire. When starting it takes over cranking. In my opinion the injectors not holding pressure in fuel rail. I want to install another one way fuel check valve to the injectors fuel rail just between the fuel hose and rail. I also mention earlier the fuel injectors not shuts off the power completly it is around 0.85v at all injectors when ignition is OFF and even battery negative cable is OFF. How it could be like that this is within engine ECU only nothing else. Something keeps power in the system most likely capasitors releasing pressure from injectors.

[Annddrriy]

I am thinking to install diodes to the engine ECU pins 16 and 17. I don't know if this is good idea.

[E32FAN]

I am thinking to install diodes to the engine ECU pins 16 and 17. I don't know if this is good idea.

I do not think that will help at all. The residual voltage might be 0.85 V, but no current is flowing. A red herring, perhaps.

Page 1360-03.

[Annddrriy]

Here is why OBD1 can not communicate with ABS module. OBD1 adapter pins 11 and 12 not used with OBD2 adapter
OBD1-adapter BM-1B with OBD2 adapter DA-5
1-not used - but in diagram is ignition coil timing control
2-not used
3-not used
4-not used
5-not used
6-not used
7-service upper very right 8-th and lower very left 9-th
8-lower 11-th
9-not used
10-not used
11-not used but in diagram terminal 50 voltage ignition switch in start
12-not used but in diagram terminal 61 D+ alternator charge indicator
13-not used but in diagram terminal TAS vehicle speed 750iL only
14-terminal 30 voltage hot at all times upper 7-th
15-terminal RXD diagnostic data link upper 4-th
16-not used but in diagram terminal 15S voltage ignition switch in run
17-not used in diagram but used in OBD1 pin 17 with OBD2 upper 7-th
18-in diagram DME-program connect but in OBD1 with OBD2 not used
19-in diagram terminal 31 ground in OBD1 pin 19 with OBD2 lower 15-th
20-terminal TXD transmit in OBD1 pin 20 with OBD2 very right 16-th

[Annddrriy]

KOEO at alternator B+ 12v and D+ 2v only is alternator D+ post bad ? KOER at alternator post B+ is big wire around 10 mm diameter 14.42v and at alternator post D+ small wire around 3mm diameter 14.52v. Which alternator post will be B+ and D+ ? Thanks in advance for your answer !

[shogun]

B+ must go to the battery positive. The battery should show 12.5 volts without the engine running. D+ is for the exciter, alternator dash signal light and voltage regulator circuit. This must also be showing 12.5 volts when the engine is not running, but the ignition switch is on. This is info from the internet, double check with ETM.
B+ Battery Battery positive connection'
D+ Warning light the name comes from the old ‘Dynamo Positive’ on a generator = this is the thin wire and terminal

[Annddrriy]

D+ is for the exciter, alternator dash signal light and voltage regulator circuit. This must also be showing 12.5 volts when the engine is not running, but the ignition switch is on if not 12.5v then alternator wiring connection not good ?

[shogun]

check the wiring from alternator to cluster. On my 750 the exciter wire D+ has a plug next to the B+ post http://bmwe32.masscom.net/sean750/sp...gConnector.jpg
the plug has 3 wires, blue from exciter plus brown and pink from engine oil level sensor, from there it goes to the cluster back yellow plug X16, pin 5 http://www.e32-schrauber.de/bmw/date...ung-x16-88.pdf pin 5, A = output, wire size 0,5, color blue, to LIMA/alternator, for charging control/Ladekontrolle x16/7

[Annddrriy]

Do you mean B+ is a battery big wire and D+ exciter wire it is on side of pentosin canister B+ wire is close to the engine block ?

[shogun]

B+ is on my 750 this big bolt http://bmwe32.masscom.net/sean750/sp...gConnector.jpg and on my 750 D+ exciter wire is the plug next to it.
on your 735 it looks like this, B+ shown and 13 is the cable harness https://www.bmwautoparts.net/en/cata...2_0333/0/47344 and the 3 wire harness includes probably the exciter wire from alternator D+ to the cluster

more explanations on D+ and B+ by E32FAN https://www.bimmerforums.com/forum/s...ing&p=30839591

[Annddrriy]

M30 engine has 140Amp alternator with wto output power terminals one of the terminal is big stud around 10mm diameter and goes to battery post + if this is B+ then when KOEO 12.5v and another terminal is smaller stud around 3mm diameter which is go to charging battery diagnostic indicator on cluster when KOEO 2v only and when KOER both terminals have to 14.45v. Smaller terminal stud don't have 12.5v when KOEO. How to fix that ? To make it both terminals 12.5v when KOEO. Thanks in advance for your answer !

[Annddrriy]

May to test to place bit battery cable to small alternator stud to check if B+ will have 12.5v when KOEO ? if YES then alternator wiring connection not good this is easy to fix by replacing B+ with D+ just wire connectors.

[E32FAN]

May to test to place bit battery cable to small alternator stud to check if B+ will have 12.5v when KOEO ? if YES then alternator wiring connection not good this is easy to fix by replacing B+ with D+ just wire connectors.

DO NOT JUMPER D+ TO B+!

That will burn out your alternator field coil.

The exciting current is limited by the Battery Lamps in the cluster. This is enough field current to get your alternator generating power when it spins.

[Annddrriy]

Does alternator B+ and D+ both terminals diodes inside the alternator ? If you put power to B+ terminal it won't go through unless diodes bad. Is same thing with D+ ?

[E32FAN]

Does alternator B+ and D+ both terminals diodes inside the alternator ? If you put power to B+ terminal it won't go through unless diodes bad. Is same thing with D+ ?

No. D+ feeds the field coils. It has a thin 0.5 BLU wire.

B+ is fed by the stator windings, through the diodes to charge the battery. It has a thick BLK cable.

This is shown on page 1230-01.


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[Annddrriy]

Ok. How many volts should be at exciter blue wire if that wire is not connected to the D+ of the alternator terminal when KOEO ?