Engine Electrical System - Repair BMW Z4 E85/E86

12 00 Contents of Engine Electrical System General

General Information

1. Working on ignition system Always switch off ignition before working on ignition system. Never touch components under current with engine running! Dangerous high tension! Always remove DME master relay for the compression test to avoid activation of ignition coils by ignition final stages of the DME control unit. Dangerous high tension! Always switch off ignition before connecting /disconnecting Service Tester, other testers and adapters or replacing components! The secondary side (high voltage side) of ignition system must be under load of at least 4 kohms. Never start engine after removing distributor cap or disconnecting wire (terminal 4) on ignition coil (terminal 4). Never connect a shielded capacitor or test light on ignition coil terminal 1. Never connect ignition coil terminal 1 wire earth or battery positive. For this reason, terminal 1 wire may not be used to interlock starting when service installing a burglar alarm system.
2. Removing And Installing Electronic Control Units CAUTION: Disconnecting the vehicle battery will cancel the fault memories of control units. For this reason, before disconnecting the battery, connect up BMW SERVICE TESTER or DIS. DIS: (select Expert mode) interrogate fault memory and print out fault messages stored in memory. BMW SERVICE TESTER: Interrogate fault memory and print out fault messages stored in memory. Investigate stored faults. Ignition must always be switched off before disconnecting or connecting control-unit connectors. Removal and installation of components, relays, fuse, etc. could cause the storage of faults in fault memories of control units capable of self-diagnosis. For this reason, fault memories must always be interrogated after working on the electrical system. Stored faults must be investigated and cancelled. When Replacing Control Unit Of DME (Digital Motor Electronics), Please Note The Following Points: Each control unit is programmed with certain basic values, which serve as mean values. The control unit receives different input values, depending on engine condition, which are compared with the stored values. The adaptive system compares the input values with the stored map values. Appropriate correction commands are sent to the concerned drive elements. If, for example, the DME control unit would be without current for a long time (more than an hour), its adaptive system would lose the stored values. After re-commissioning a cancelled unit or installing a new control unit, the input values of the relevant engine must be read in and stored for the adaptive system. This procedure could lead to erratic idling and disturbed overrunning of the engine after starting. Depending on the engine it could require some time before all values are adapted to the engine condition. For this reason, follow the procedure described below before replacing or reinstalling a DME control unit: Run engine to operating temperature if possible before replacing the control unit. Remove control unit, install new control unit and drive vehicle.
3. Welding Work (Overload Protection Of Control Units) When performing welding work on installed control units, to avoid any defects in the electronic control units, observe the following steps: Observe instructions for disconnecting and connecting battery. See INSTRUCTIONS FOR DISCONNECTING AND CONNECTING BATTERY. Detach terminal of battery negative lead from car battery and second battery if fitted. Cover negative terminal posts. If welding is to be performed near the battery/batteries, first remove battery/batteries from vehicle (flying sparks - combustion of explosive gas). Fit return clamp on welding unit as close as possible to welding point (maximum distance approx. 1 mm). Never connect return clamp to ground pin on body which has ground wires attached!
4. Disconnecting and connecting battery . Observe safety instructions for handling vehicle battery. Refer to «Safety Instructions For Handling Vehicle Battery»(/bmw/z4/e85e86-2002-2005/remont/gauges-instrument-panels/#engine-electrical-system-repair__12-00-instructions-for-disconnecting-and) . Before Disconnecting Battery: Switch off ignition. NOTE: If the ignition is not turned off when the battery is disconnected, fault memories may be set in some control units. Important! There is a danger of mixing up battery leads: If the battery positive and negative leads are the same color and you are in doubt, follow the polarity to the battery, then mark and cover the leads. On vehicles with radio code: After disconnecting the battery, the radio code must be re-entered. Therefore obtain the radio code card from the customer beforehand. Note stored stations and restore them after connecting the battery. Stored settings of the on-board computer and clock will also be lost. All available central keys must be receded for cars with first generation infrared transmitter locking systems. General Notes On Disconnecting Battery: Do not disconnect battery leads and leads from alternator and starter motor while engine is running. Cars with IBS on battery negative terminal: Do not under any circumstances pull/lever off pole shoes by force. Do not under any circumstances release socket-head cap screw of IBS. When work is carried out on the electrical system, faults may be caused in the fault memories of some control units when the battery is connected. After Connecting Battery: Important! After a power supply interruption some equipment is disabled and must be reactivated. For further information and instructions on vehicle-specific activation, please refer to PROCEDURE FOR INITIALIZATION .
5. Disconnecting and connecting test equipment When connecting and disconnecting: Service Tester. Testing Devices. Test Leads. When Replacing Control Units. It is essential to turn off the ignition. Follow instructions for removing and installing electronic control units. See REMOVING AND INSTALLING ELECTRONIC CONTROL UNIT. Follow operating instructions for testing devices. Make sure that connected test leads cannot make contact with rotating parts (e.g.: fans, ribbed V-belts, etc.).
6. Component inspection NOTE: On all inspections and operations on the engine electrics and electronics, comply with prevailing national safety legislation and accident prevention regulations. Always disconnect connectors of control units or components before checking electric wires. Testing Aids: The relevant wiring diagrams are filed in the Electrical Troubleshooting Manual folder for the 3 Series E36. Always use correctly produced inspection lines, adapters, terminals and test tips. Test values for checking components are contained in the Electrical Troubleshooting Manual. For further technical information, refer to «ENGINE ELECTRICAL SYSTEM - TECHNICAL DATA»(ref-202372) .
7. External Jump-Starting Aid Do not start the engine with help of starting sprays. Preparation Conform with the following when starting engine with starting cable. Ensure that starting cable wires are to appropriate cross-section size. Only use fuse-protected starting cables. Check whether the current supplying battery has 12V voltage. If engine is started from battery of another vehicle, ensure that there is no contact between the bodies of both vehicles. CAUTION: Never touch ignition system components under current - dangerous high tension! Operation: Always conform with the procedures to avoid injury to persons or damage to parts. Select range P in vehicles with an automatic transmission and apply the parking brake. Move the shift lever of vehicles with manual transmission into neutral and apply the parking brake. Ensure that the starting cables cannot get caught in rotating parts, e.g. fan. First connect both positive poles of the batteries with one starting cable (red). Use the positive connection point in the engine compartment for vehicles with the battery in the trunk. Then connect the second starting cable (black) between the negative pole of the current supplying battery and engine or body earth of the vehicle to be started. CAUTION: Never connect the second starting cable (black) on the negative pole of the battery in the vehicle to be started. Produced gas could be ignited by sparks. Danger of explosion! If the battery in the vehicle supplying power is weak, start the engine of this vehicle and let it run at idling speed. After the engine of the vehicle to be started has started up, first disconnect the starting cable on the negative pole/earth connection. Then remove the starting cable from the positive poles.
8. Compression Testing See «11 00 039 CHECKING COMPRESSION OF ALL CYLINDERS»(/bmw/z4/e85e86-2002-2005/remont/mechanical/#engine-repair-m54__11-00-039-checking-compression-of) .

12 00... Instructions for disconnecting and connecting battery

Observe safety instructions for handling vehicle battery .

Before disconnecting battery

Switch off ignition.

Note. If the ignition is not turned off when the battery is disconnected, fault memories may be set in some control units.

General notes on disconnecting battery

1. Do not disconnect battery leads and leads from alternator and starter motor while engine is running.
2. Cars with IBS on battery negative terminal: Do not under any circumstances pull/lever off pole shoes by force. Do not under any circumstances release socket-head cap screw of IBS.
3. Detach terminal of battery negative lead from car battery and second battery if fitted. Cover battery negative terminal(s) and secure.
4. When work is carried out on the electrical system, faults may be caused in the fault memories of some control units when the battery is connected.
5. When fitting terminal for battery negative lead. Tightening torque, see 61 21 1AZ in «GENERAL ELECTRICAL SYSTEM - TIGHTENING TORQUE»(/bmw/z4/e85e86-2002-2005/remont/horns/#general-electrical-system-tightening-torques) .

After connecting battery

12 13 Notes on checking ignition system

Troubleshooting

1. > «12 13 ... FAULT IN FUEL INJECTION SYSTEM»(ref-202355-S23205695302005112100000)
2. > «12 13 ... SPARK-PLUG FAULTS»(ref-202355-S26389167732005112100000)
3. > «12 13 ... IGNITION COIL FAULTS»(ref-202355-S26903262322005112100000)
4. > «12 13 ... FURTHER FAULT PATTERNS WITH EVALUATION»(ref-202355-S19482276232005112100000)
5. > «12 13 ... ADDITIONAL FAULT NOTES FOR TROUBLESHOOTING»(ref-202355-S18680020132005112100000)

Oscillograms

1. > «12 13 ... NORMAL OSCILLOGRAM»(ref-202355-S12776500672005102700000)
2. > «12 13 ... OSCILLOGRAMS OF IGNITION COILS FROM DIFFERENT MANUFACTURERS»(ref-202355-S03729079832005112100000)

Check

1. > «12 13 ... CHECKING SECONDARY SIGNAL FOR STATIONARY IGNITION DISTRIBUTION»(ref-202355-S14783701662005102700000)

12 12 011 Replacing all spark plugs

Special tools required

1. 12 1 171
2. 12 1 200

Note. This repair instruction is valid for the following engines: M52 / M52TU / M54 / M56 S52 / S50US

Necessary preliminary tasks

1. Remove ignition coils .

Unscrew and remove spark plugs with special tool 12 1 171 in conjunction with special tool 12 1 200.

Installation

If special tool 12 1 200 is not used

Tightening torque, see 12 12 1AZ in ENGINE ELECTRICAL SYSTEM - TIGHTENING TORQUES .

Scheme 1

Troubleshooting

1. > «12 13 ... FAULT IN FUEL INJECTION SYSTEM»(ref-202355-S23205695302005112100000)
2. > «12 13 ... SPARK-PLUG FAULTS»(ref-202355-S26389167732005112100000)
3. > «12 13 ... IGNITION COIL FAULTS»(ref-202355-S26903262322005112100000)
4. > «12 13 ... FURTHER FAULT PATTERNS WITH EVALUATION»(ref-202355-S19482276232005112100000)
5. > «12 13 ... ADDITIONAL FAULT NOTES FOR TROUBLESHOOTING»(ref-202355-S18680020132005112100000)

Oscillograms

1. > «12 13 ... NORMAL OSCILLOGRAM»(ref-202355-S12776500672005102700000)
2. > «12 13 ... OSCILLOGRAMS OF IGNITION COILS FROM DIFFERENT MANUFACTURERS»(ref-202355-S03729079832005112100000)

Check

1. > «12 13 ... CHECKING SECONDARY SIGNAL FOR STATIONARY IGNITION DISTRIBUTION»(ref-202355-S14783701662005102700000)

12 13... Checking secondary signal for stationary ignition distribution

Special tools required

1. 12 7 030

Engine Test Step 10

Remove ignition coil. Clip Special Tool 12 7 030 on relevant ignition coil to be tested. Clip high tension clip around ignition lead.

Scheme 2

Connect earth lead of adapter to vehicle earth and ignition coil.

Connect up diagnosis connector.

If trigger signal is not present (terminal 1), connect black clip of universal adapter cable to pin 1 of primary adapter cable.

Scheme 3

Produce a stationary signal by pressing key R on the tester.

Note. Neighboring ignition leads could produce interference on the screen of the oscilloscope.

Refer to the fault memories of engine control units for additional troubleshooting.

Interrogate fault memory and its fault reports.

Scheme 4

Scheme 5

1. start of ignition voltage peak
2. Level of ignition voltage
3. Level of combustion voltage
4. Period of combustion
5. Combustion curve characteristics
6. Start of decay process
7. Termination oscillations

Secondary voltage patterns, beside one another

Evaluation of ignition voltage peaks at idle speed (this example shows an engine with 4 cylinders).

Note. The display of ignition voltage spikes is approx. 20-25% lower than the real value. The uniformity of all cylinders to each other is more important than the height of ignition voltage peaks. Differences of 3000... 4000 V are permitted. In event of greater differences, refer to Further Fault Patterns With Evaluation .

Scheme 6

Evaluation of ignition voltage peaks at increased speed of approx. 2000 RPM (this example shows an engine with 4 cylinders).

Scheme 7

Secondary voltage diagrams, superimposed

Evaluation of combustion characteristics curve and decay characteristics at idle speed (this example shows a 4-cylinder engine).

Scheme 8

Secondary voltage diagrams, consecutive

Note. Only the major differences in the ignition voltage patterns are revealed by this method of comparison. The identified fault must be allocated to the relevant cylinder using the secondary voltage representation forms next to/on top of each other.

Scheme 9

12 13 009 Checking rod-type ignition coils (M54)

Special tools required

1. 12 1 301
2. 12 7 050

Necessary preliminary tasks

1. Remove ignition coil cover.

Unlock plug fastener (1) of ignition coil.

Scheme 10

Detach plug (1) in direction of arrow.

Pull out ignition coil (2) towards top.

Note. Procedure applies to all rod-type ignition coils.

Scheme 11

Install special tool 12 7 050.

Installation

Special tool 12 7 050 is attached between spark plug and rod type ignition coil.

Scheme 12

Secondary measurement

Connect KV clip-on probe (1) of DIS Tester to special tool 12 7 050.

Procedure on DIS Tester

1. Select < Measurement >.
2. Select < Preset measurement >.
3. Select < Secondary ignition signal >.
4. Connect < TD cable to diagnostic head >.
5. Select < static ignition distribution >.
6. Select < Number of cylinders >.

For subsequent procedure, follow DIS instructions.

Scheme 13

Primary measurement

Connect 26-pin pin box with special tool 12 1 301 to connector (1) DME module 5.

Procedure on DIS Tester

1. Select < Measurement >.
2. Select < Preset measurement >.
3. Select < Ignition signal term.1 >.

For subsequent procedure, follow DIS instructions.

Note. Pin assignment acc. to connection scheme.

Scheme 14

Illustration of multiple spark ignition

Scheme 15

1. Start of ignition peak.
2. Level of ignition voltage.
3. Level of sparking voltage.
4. Spark duration.
5. Sparking voltage curve.
6. Start of decay process.
7. Decay process.

M54 / M56 / N40 / N42 / N45 / N46 / N62 / N73

The following ignition oscillogram applies to engines with multiple spark ignition from a production date of April 2001

Depending on engine temperature (approx. -20° to 100°) and engine speed (< 2000 RPM.), some ignition voltage peaks (approx. 1-5 ignition peaks) can occur before the typical ignition voltage characteristic.

The additional ignition peaks play no role in diagnosis.

The last ignition peak (1) on the oscillogram is decisive.

Scheme 16

Note. The display of the ignition voltage peak is approx. 20-25 % lower than the real value.

It is not the height of the ignition voltage peaks but rather the uniformity of all the cylinders that is important.

Differences of 3000 to 4000 volts are permitted.

12 13 511 Replacing ignition coils (M54)

Necessary preliminary tasks

1. Check stored fault messages.
2. Switch off ignition.
3. Remove E65/66 center assembly wall .
4. Remove ignition coil cover .

Unlock plug retainer of ignition coil (1) and disconnect plug.

Pull ignition coil (1) up and out.

This procedure is applicable to all ignition coils.

Scheme 17

Installation

Check that rubber seal of ignition coil (1) is correctly seated.

Scheme 18

Note. Read out fault memory of DME control unit.

Now clear the fault memory.

12 14 521 Replacing pulse generator on crankshaft (M54/M56)

Necessary preliminary tasks

1. Read out fault memory of DME control unit
2. Switch off ignition
3. E46, E60, E61 only: Remove reinforcement plate on front axle support. See «51 71 374 REMOVING AND INSTALLING/REPLACING REINFORCEMENT PLATE»(/bmw/z4/e85e86-2002-2005/remont/door-locks-anti-theft-systems/#body-equipment-repair__51-71-374-removing-and-installingreplacing) .

1. If fitted: Remove vacuum reservoir for exhaust flap.

All models

Note. Installation location of pulse generator for crankshaft is underneath starter motor.

Note. For a better overview, this work step is shown on an engine that has been removed.

Unlock plug (1) and remove.

Unscrew bolt (2).

Remove pulse generator (3).

Scheme 19

Note. Check stored fault messages.

Now clear the fault memory.

12 14 523 Replacing pulse generator on inlet camshaft (M52TU / M54 / M56)

Necessary preliminary tasks

1. Check stored fault messages.
2. Switch off ignition.
3. Remove suction filter housing .

Note. Arrow shows installation position of pulse generator.

Remove solenoid valve (1) of VANOS adjustment unit for inlet camshaft.

Installation

Replace sealing ring.

Tightening torque, see 11 36 1AZ in ENGINE - TIGHTENING TORQUES .

Scheme 20

Disconnect plug connection (1) on cable duct (2).

Scheme 21

Release screw (1) on pulse generator (2).

Remove pulse generator (2) from cylinder head.

Note. To facilitate installation of pulse generator lead: Secure an approx. 50 cm long auxiliary lead to plug connection of pulse generator.

Feed out end of pulse generator lead but only to such an extent that the auxiliary lead remains in the original routing in the intake system.

Remove pulse generator with lead.

Disconnect auxiliary lead from faulty pulse generator. Secure plug connection of new pulse generator to auxiliary lead.

Using auxiliary lead, feed new lead of pulse generator through to cable duct at bottom.

Scheme 22

Installation

Check sealing ring for possible damage, replace if necessary.

Note. Read out fault memory of DME control unit.

Now clear the fault memory.

12 14 524 Replacing pulse generator on exhaust camshaft (M52TU, M54, M56)

Necessary preliminary tasks

1. Check stored fault messages.
2. Switch off ignition.

Location

On cylinder head at front on exhaust side.

Unlock plug (1) and detach from pulse generator.

Scheme 23

Release screw (1) on cylinder head.

Remove pulse generator.

Installation

Check sealing ring for possible damage, replace if necessary.

Scheme 24

Note. Interrogate fault memory of DME control unit.

Rectify faults.

Now clear the fault memory.

12 14 600 Replacing knock sensor (M52TU, M54,M56)

Necessary preliminary tasks

1. Check stored fault messages.
2. Switch off ignition.
3. Remove intake air manifold. See «11 61 050 REMOVING AND INSTALLING INTAKE AIR MANIFOLD»(/bmw/z4/e85e86-2002-2005/remont/mechanical/#engine-repair-m54__11-61-050-removing-and-installing) .

Unclip plug connection (1) from holder of cable duct (2) and disconnect.

Scheme 25

Release screw (1) and remove knock sensor for cylinder bank 1-3.

Scheme 26

Release screw (2) and remove knock sensor for cylinder bank 4-6.

Scheme 27

Installation

Clean support face of knock sensors on engine block.

Tightening torque, see 12 14 2AZ in ENGINE ELECTRICAL SYSTEM - TIGHTENING TORQUES .

Scheme 28

Installation

Read out fault memory of control unit of Digital Motor Electronics (DME).

Now clear the fault memory.

12 14 700 Coding control module (DME)

Switch off ignition.

Connect MoDiC or DIS/GT1 Tester.

Switch on ignition.

Select "Coding" program.

For subsequent procedure, follow instructions in MoDiC or DIS/GT1 Tester.

Carry out adjustment of following control units

1. EWS (electronic immobilizer)
2. DME (Digital Motor Electronics) or

12 14 705 Programming control unit (DME)

Switch off ignition.

Connect MoDiC or DIS/GT1 Tester.

Switch on ignition.

Select "Programming".

For subsequent procedure, follow instructions in MoDiC or DIS/GT1 Tester.

Carry out adjustment of following control units

1. EWS (electronic immobilizer)
2. DME (Digital Motor Electronics) or

12 31... Replacing alternator belt pulley

Special tools required

1. 12 7 110

Remove and install alternator drive belt.

Depending on alternator type, grip shaft with

1. hexagon socket
2. multi-tooth socket or
3. Torx socket wrench

Release nut with special tool 12 7 110.

Installation

Tightening torque, see 12 31 2AZ / 12 31 3AZ in ENGINE ELECTRICAL SYSTEM - TIGHTENING TORQUES .

Scheme 29

12 31 009 Checking alternator (BSD)

Necessary preliminary tasks

1. Correct connections on charged battery
2. Correct connections on alternator and starter motor
3. Good ground connection between engine and body
4. Tensioned ribbed V-belt
5. Read out DME fault memory.

Note. The alternator with BSD interface can communicate with the engine control unit (DME).

The alternator is not connected to the charge telltale light.

The alternator can identify various faults.

BSD alternator can be recognized by the plug connection on the alternator.

Connect diagnosis tester.

1. Function selection
2. Complete vehicle
3. Drive
4. Voltage and current regulation
5. Voltage and current generation
6. Alternator
7. Follow instruction in diagnostic program

Oscillogram for a fault-free alternator

Scheme 30

Oscillogram for a faulty alternator

One phase interrupted.

Repair/exchange alternator.

Scheme 31

Interturn fault.

Repair/exchange alternator.

Scheme 32

Open circuit in negative diode.

Repair/exchange alternator.

Scheme 33

Short circuit in positive diode.

Repair/exchange alternator.

Scheme 34

Open circuit in positive diode.

Repair/exchange alternator.

Scheme 35

Open circuit in exciter diode.

Repair/exchange alternator.

Scheme 36

Assemble engine.

Check function of DME.

12 31 009 Checking alternator and regulator switch

Test requirements

1. Correct connections on charged battery
2. Correct connections on alternator and starter motor
3. Good ground connection between engine and body
4. Tightened drive belt

Connect DIS Tester.

1. Measurement
2. Checking alternator

If charge indicator lamp is permanently lit

Remove voltage regulator and check carbon brushes, replace if necessary.

Replace alternator regulator switch .

Note. Minimum length of carbon brushes "A" = 5 mm.

Scheme 37

If charge indicator lamp goes out while engine is running

Check control voltage.

Regulator switch must be replaced if control voltage is not achieved.

Replace alternator regulator switch .

From E46/E39 with multifunction regulator.

Recognizable by plug connection on regulator.

Connect DIS Tester.

1. Function selection
2. Complete vehicle
3. Drive
4. Voltage and current regulation
5. Voltage and current generation
6. Work through test modules

Oscillogram for a fault-free alternator

Scheme 38

Oscillogram for a faulty alternator

One phase interrupted.

Repair/exchange alternator.

Scheme 39

Interturn fault.

Repair/exchange alternator.

Scheme 40

Open circuit in negative diode.

Repair/exchange alternator.

Scheme 41

Short circuit in positive diode.

Repair/exchange alternator.

Scheme 42

Open circuit in positive diode.

Repair/exchange alternator.

Scheme 43

Open circuit in exciter diode.

Repair/exchange alternator.

Scheme 44

12 31 020 Removing and installing or replacing alternator (M54)

Necessary preliminary tasks

1. Check stored fault messages.
2. Switch off ignition.
3. Observe «Instructions For Disconnecting And Connecting Battery»(/bmw/z4/e85e86-2002-2005/remont/gauges-instrument-panels/#engine-electrical-system-repair__12-00-instructions-for-disconnecting-and) .
4. Disconnect battery ground wire and mask it.
5. Remove suction filter housing .
6. Remove Alternator Drive Belt .

Unlock and detach plug connection (1).

Release nut (2) and remove battery positive lead.

Tightening torque, see 12 31 1AZ in ENGINE ELECTRICAL SYSTEM - TIGHTENING TORQUES .

Scheme 45

Remove cover from idler pulley (1).

Release screw and remove idler pulley (1).

Release screw and remove alternator (2).

Scheme 46

Installation

Turning lock of tensioning roller must engage in alternator groove.

Scheme 47

Note. Read out fault memory of DME control unit.

Now clear the fault memory.

12 41 020 Removing and installing/replacing starter motor (M54)

Necessary preliminary tasks

1. Follow «Instructions For Disconnecting And Connecting Battery»(/bmw/z4/e85e86-2002-2005/remont/gauges-instrument-panels/#engine-electrical-system-repair__12-00-instructions-for-disconnecting-and) .
2. Disconnect battery negative lead from battery
3. Remove intake filter housing

Note. All the tasks can be performed from above.

Release nut (1) and remove lead from starter motor.

Installation

1. Tightening torque, see 12 41 4AZ in «ENGINE ELECTRICAL SYSTEM - TIGHTENING TORQUES»(/bmw/z4/e85e86-2002-2005/remont/gauges-instrument-panels/#engine-electrical-system-tightening-torques) .

Release nut (2) and remove battery positive leads from starter motor.

Installation

1. Tightening torque, see 12 41 4AZ in «ENGINE ELECTRICAL SYSTEM - TIGHTENING TORQUES»(/bmw/z4/e85e86-2002-2005/remont/gauges-instrument-panels/#engine-electrical-system-tightening-torques) .

Release screws (3) and remove starter motor (4).

Scheme 48

Installation

Tightening torque, see 12 41 1AZ in ENGINE ELECTRICAL SYSTEM - TIGHTENING TORQUES .

Installation

Check starter motor pinion and ring gear for damage.

Scheme 49

12 41 041 Replacing solenoid switch

Turn off ignition.

Remove starter motor. See 12 41 020 Removing And Installing/Replacing Starter Motor (M54) .

Release nut (1).

Remove cable lug (2).

Scheme 50

Release screws (1).

Scheme 51

Remove solenoid switch (1) and spring (2).

Unhook pin (3).

Installation

Check pin (3) for wear and apply grease.

Scheme 52

12 42 540 Replacing safety battery terminal (SBK)

Necessary preliminary tasks

1. Remove luggage compartment floor trim panel. See «51 47 101 REMOVING AND INSTALLING/REPLACING LUGGAGE COMPARTMENT FLOOR TRIMS»(/bmw/z4/e85e86-2002-2005/remont/door-locks-anti-theft-systems/#body-equipment-repair__51-47-101-removing-and-installingreplacing) .
2. Follow instructions for «Instructions For Disconnecting And Connecting Battery»(/bmw/z4/e85e86-2002-2005/remont/gauges-instrument-panels/#engine-electrical-system-repair__12-00-instructions-for-disconnecting-and) .
3. Disconnect battery negative lead and cover.
4. Loosen electrical system cable.
5. Remove battery.

Note. The safety battery terminal is replaced together with a complete cable up to the battery positive terminal in the engine compartment.

Unlock cover on terminal and remove.

Unlock both plug connections (1) and disconnect.

Release nut on electrical system cable (2).

Scheme 53

Unclip plug connection (1), unlock and disconnect.

Release nut on electrical system cable (2).

Scheme 54

Remove left rear wheel .

Release screws on cover frame (1).

Unscrew nuts (2).

Feed battery positive lead out of battery well.

Scheme 55

Scheme 56

Cut through cable ties (1).

Unlock holder (2) and unclip positive lead.

Release nut (3) and remove holder.

Compress holder (4) and detach.

If necessary, unclip plastic line (1).

If necessary, unclip brake lines (2).

If necessary, release lead (3) from ABS sensor and disconnect.

Scheme 57

Feed out battery positive lead in direction of battery well to right and remove.

Installation

If necessary, replace faulty fuses.

12 51 001 Replacing wiring harness section for engine (M54)

Necessary preliminary tasks

1. Switch off ignition
2. Follow «Instructions For Disconnecting And Connecting Battery»(/bmw/z4/e85e86-2002-2005/remont/gauges-instrument-panels/#engine-electrical-system-repair__12-00-instructions-for-disconnecting-and) . Disconnect battery negative lead and cover
3. Remove intake air manifold . See «11 61 050 REMOVING AND INSTALLING INTAKE AIR MANIFOLD»(/bmw/z4/e85e86-2002-2005/remont/mechanical/#engine-repair-m54__11-61-050-removing-and-installing) .
4. Remove ignition coil cover .
5. Remove reinforcement plate . See «51 71 374 REMOVING AND INSTALLING/REPLACING REINFORCEMENT PLATE»(/bmw/z4/e85e86-2002-2005/remont/door-locks-anti-theft-systems/#body-equipment-repair__51-71-374-removing-and-installingreplacing) .

WIRING HARNESS SECTION REPLACEMENT WORK STEP

12 51 100 Replacing wiring harness section for ignition coils (M54)

Necessary preliminary tasks

1. Read out fault memory of DME control unit
2. Switch off ignition
3. Disconnect battery negative lead from battery. Follow «Instructions For Disconnecting And Connecting Battery»(/bmw/z4/e85e86-2002-2005/remont/gauges-instrument-panels/#engine-electrical-system-repair__12-00-instructions-for-disconnecting-and) .
4. Remove cover for ignition coils

Unfasten screws.

Open cover (1) of electronics box and remove.

Scheme 58

Unlock plug (1) and detach from DME control unit.

Unlock plug (2) and remove.

Lift wiring harness with profile seal (3) out of electronics box.

Installation

To prevent leaks, you must install profile seal (3) correctly.

Scheme 59

Unlock plug retainer (1) of ignition coil and disconnect plug.

Note. This procedure is applicable to all ignition coils.

Release nuts and remove grounding cable.

Unclip cable duct (2).

Unclip wiring harness (3) and remove.

Scheme 60

Note. Now clear the fault memory.

12 61 250 Removing and installing/replacing oil temperature sensor (M54)

Necessary preliminary tasks

1. Switch off ignition
2. Unfasten oil filter cap to enable engine oil in filter to flow back into the oil sump.
3. Remove intake filter housing . See «11 61 050 REMOVING AND INSTALLING INTAKE AIR FILTER HOUSING»(/bmw/z4/e85e86-2002-2005/remont/mechanical/#engine-repair-m54__11-61-050-removing-and-installing) .

Installation location: at base of oil filter.

Disconnect plug connection (1).

Unscrew oil temperature sensor.

Installation

Tightening torque, see 12 61 1AZ in ENGINE ELECTRICAL SYSTEM - TIGHTENING TORQUES .

Screw on oil-filter cover tightly.

Check engine oil level, top up engine oil if necessary.

Scheme 61

12 61 280 Removing and installing/replacing oil pressure sensor (M54)

Necessary preliminary tasks

1. Switch off ignition
2. Unfasten oil filter cap to enable engine oil in filter to flow back into the oil sump.
3. Remove intake filter housing See «11 61 050 REMOVING AND INSTALLING INTAKE AIR FILTER HOUSING»(/bmw/z4/e85e86-2002-2005/remont/mechanical/#engine-repair-m54__11-61-050-removing-and-installing) .

Installation location: at base of oil filter.

Disconnect plug connection (2).

Unscrew and remove oil-pressure switch.

Tightening torque, see 12 61 1AZ in ENGINE ELECTRICAL SYSTEM - TIGHTENING TORQUES .

Installation

Screw on oil-filter cover tightly.

Check engine oil level, top up engine oil if necessary.

Scheme 62

12 61 285 Replacing level switch for engine oil

Necessary preliminary tasks

1. Switch off ignition.
2. Unfasten oil filter cover to enable engine oil in filter to flow back into the oil pan.
3. Remove underbody panelling.
4. If necessary, remove reinforcing plate . See «51 71 374 REMOVING AND INSTALLING/REPLACING REINFORCEMENT PLATE»(/bmw/z4/e85e86-2002-2005/remont/door-locks-anti-theft-systems/#body-equipment-repair__51-71-374-removing-and-installingreplacing) .
5. Drain engine oil.

Disconnect plug connection (1).

Unscrew nuts (2).

Remove level switch (3).

Scheme 63

Installation

Clean sealing face on oil sump.

Replace seal on level switch.

Installation

Top up engine oil.

Screw on oil-filter cover tightly.

Tightening torque, see 11 42 2AZ in ENGINE - TIGHTENING TORQUES .

12 61 285 Replacing oil level sensor

Necessary preliminary tasks

1. Switch off ignition
2. Unfasten oil filter cap to enable engine oil in filter to flow back into the oil sump
3. Remove reinforcement plate . See «51 71 374 REMOVING AND INSTALLING/REPLACING REINFORCEMENT PLATE»(/bmw/z4/e85e86-2002-2005/remont/door-locks-anti-theft-systems/#body-equipment-repair__51-71-374-removing-and-installingreplacing) .
4. Drain off engine oil

Unlock plug (1) and remove.

Unscrew nuts.

Remove oil level sensor (2).

Installation

Clean sealing face on oil sump.

Replace seal on oil level sensor.

Tightening torque, see 12 61 2AZ in ENGINE ELECTRICAL SYSTEM - TIGHTENING TORQUES .

Scheme 64

Installation

Top up engine oil.

Tighten down oil filter cap.

Tightening torque, see 11 42 2AZ in ENGINE - TIGHTENING TORQUES .

12 90 100 Replacing fan for electronics box

Unfasten screws.

Open electronics box cover (1).

Release relay plug on reverse side of cover.

Remove cover.

Installation

Make sure that cover is correctly inserted in hinges of electronics box lower section (water tightness).

Scheme 65

Raise control unit slightly.

Unlock plug connection (1) and detach from equipment carrier.

Unfasten plug connection and disconnect.

Scheme 66

Lever out expander rivet.

Release screws (1).

Remove cover (2).

Scheme 67

Unfasten screws.

Remove fan (1).

Scheme 68

See also:
• 11 00 039 CHECKING COMPRESSION OF ALL CYLINDERS
• GENERAL ELECTRICAL SYSTEM - TIGHTENING TORQUE
• ENGINE ELECTRICAL SYSTEM - TIGHTENING TORQUES
• 51 71 374 REMOVING AND INSTALLING/REPLACING REINFORCEMENT PLATE
• 11 61 050 REMOVING AND INSTALLING INTAKE AIR MANIFOLD
• 51 47 101 REMOVING AND INSTALLING/REPLACING LUGGAGE COMPARTMENT FLOOR TRIMS
• 13 62 531 REPLACING COOLANT TEMPERATURE SENSOR
• 13 54 030 REMOVING AND INSTALLING/SEALING THROTTLE VALVE ASSEMBLY
• 11 36 570 REPLACING SOLENOID VALVE FOR INLET
• 11 36 575 REPLACING SOLENOID VALVE FOR EXHAUST
• SYSTEM & COMPONENT TESTING
• Safety Instructions For Handling Vehicle Battery
• 12 41 020 Removing And Installing/Replacing Starter Motor (M54)
• 12 61 285 Replacing Oil Level Sensor
• 12 14 521 Replacing Pulse Generator On Crankshaft (M54/M56)
• 12 14 523 Replacing Pulse Generator On Inlet Camshaft (M52TU / M54 / M56)
• 12 14 524 Replacing Pulse Generator On Exhaust Camshaft (M52TU, M54, M56)
• 12 61 280 Removing And Installing/Replacing Oil Pressure Sensor (M54)
• 12 14 600 Replacing Knock Sensor (M52TU, M54,M56)
• 12 31 020 Removing And Installing Or Replacing Alternator (M54)