Crankshaft speed sensor, replacing (M62 and M62TU engines)
The crankshaft speed sensor reads a toothed pulse wheel mounted on the flywheel. If the Engine Control Module(ECM) does not receive an impulse signal from the crankshaft speed sensor during cranking, the engine will not start. If the OBD II system misfire detection protocol detects a catalyst damaging fault due to a malfunction in the crankshaft speed sensor components, the Check Engine light (Malfunction Indicator Light or MIL) will be Illuminated.
4 The crankshaft speed sensor (arrow) is mounted in the right lower side of the bell housing.
-Remove speed sensor by disconnecting electrical harness connector and unbolting sensor from bell housing. Do not discard shims, if present.
-Installation is the reverseof removal. Clean mounting surface before installing new sensor, and install shims, if present.
<If the flywheel was replaced, the speed sensor must be checked for correct installation depth.
*Crank engine in direction of rotation using crankshaft bolt until a full pulse tooth is centered in the opening for the removed speed sensor.
Measure depth ro top of tooth from speed sensor p ~ l s e generator mounting s~rfaceon transmission.
4 Measure length of pulse generator from mounting surface to end (A).
-Subtract length of pulse generator (A) from distance to pulse tooth from mounting area on transmission. This measurement is the gap between the pulse sensor and flywheel. Use shims available from BMW to increase gap as needed to reach specification.
Pulse sensor gap
End of sensor to flywheel teeth
0.55 +0.2 rnrn
(0.0217 t 0.008 in)
IIgnition System
Camshaft position sensors
The camshaft position sensors are used by the englne management system for VANOS control, sequentialfuel injection and knock control.
Intake camshaft positionsensor, replacing (M52,M52 TU and M54 engines)
-Make certain ignition has been turned off.
-Remove plastic cover from above fuel injectors by prying off bolt covers and removing cover mounting bolts.
Remove complete air filter housing:
Disconnect electrical harness connector on mass air flow sensor (A).
Detach vacuum line at intake boot (B).
Loosen hose clamp at intake boot and detach air duct connections (C).
* Disconnect cold air duct tube (D).
Remove filter housing mounting screws (E).
-Disconnect harness connector from VANOS solenoid and unscrew solenoid from VANOS control unit. Be preparedwith shop rags to catch oil released from VANOS unit.
Remove camshaft sensor (arrow) from left front of cyl~nder head, next to top of oil filter housing.
Disconnect camshaft sensor harness from under intake manifold. Prior to removal, attach a stiff piece of wire to the harness connector end to preserve proper routingof harness for reinstallation.
Installation is reverse of removal, noting the following:
Use new O-rings when installing sensor and solenoid.
Be sure wiring is rerouted in same orientation.
Use scan tool to read out and clear ECM fault memory
Tightening torques
-
Intake camshaft sensor to cylinder head
10 Nrn (7 ft-lb)
VANOS solenoid to VANOS control unit
30 Nm (22 ft-lb)
120-15
Ignition system1
Exhaust camshaft position sensor, replacing (M52 TU and M54 engines)
-Make sure ignition has been turned off.
4 Working at front of engine on exhaust (right) side, detach exhaust camshaft position sensor electrical harness connector (arrow) and remove sensor.
-Installation is reverse of removal, noting the following:
-Use a new O-ring when installing sensor.
Use scan tool to read out and clear ECM fault memory.
Tighteningtorque
Exhaust camshaft sensor to cylinder head
10 Nm (7 ft-lb)
Intake camshaft position sensor, replacing (M62 and M62 TU engines)
-Make sure ignition has been turned off
4 Remove top engine cover by releasing quick release fasteners (arrows) by pressing down.
4 Remove air filter housing and mass air flow sensor:
Disconnect mass air flow sensor and intalte air temperature sensor electrical harnesses (A and B).
Remove air filter housing mounting fastener (arrow). Loosen hose clamps (C and D).
Remove hose at idle air stabilizer.
-Remove air filter housing with mass air flow sensor. Remove intalte hose from throttle body.
120-16
Ignition System
Remove camshaft sensor (arrow) from front of right cylinder head.
Disconnect camshaft sensor harness from cable duct above right cylinder head.
Installation is reverse of removal, noting the following:
Use new O-ring when installing sensor.
Be sure wiring is rerouted in same orientation.
Use scan tool to read out and clear ECM fault memory.
Tightening torque
Intake camshaft sensor to timing chain cover
5 Nm (3.5 ft-lb)
Knock sensors
Knock sensors, replacing (M52, M52 TU and M54 engines)
The knock sensors are bolted to the left side of the cylinder block under the intake manifold.
-Remove intalte manifold as described in 113 Cylinder Head Removal and Installation.
D~sconnectknock sensor electrical harness connector (A) on left side of engine cylinder block.
Remove knock sensor mount~ngbolts (arrows) on side of cyllnder block. Remove sensors.
Note the installedangle of the l n o c lsensor~ on the bloc/(before removingit. Reinstallthe sensorinthesameposition. Be sure to use a torque wrench when tighteningthe sensor mounting bolt.
<Clean lknock sensor contact surface on engine bloclc and sensor (arrows) before installing ltnock sensor.
Tightening torque
Knock sensor to head
20 Nm (15 ft-lb)
-Use scan tool to read out and clear ECM fault memory. Knock sensors, replacing (M62 and M62 TU engines)
The knock sensors are bolted to the side of the cylinder block under the intake manifold.
Ignition System
Remove intake manifold as described in 113 Cylinder Head Remaval and Installation.
Remove knock sensor mounting bolts (arrows) on side of cylinder block. Remove sensors.
I CAUTION-
I
Note the installedangleof the knocksensorson the blocltbe-
fore removalit. Reinstallthe sensors in the sameposition. Be
sure to use a torque wrench when tightening the sensor
mounting bolts.
Clean lknoclc sensor contact surfaces on engine bloclc and
sensors before installing.
Tightening torque
Knock sensor to engine bloclc
20 Nm (15 ft-lb)
-Use scan tool to read out and clear ECM fault memory.
This section covers the battery, alternator, starter and associated components of the electrical system.
Troubleshooting informationforthese componentsisfoundin Table a. Battery, alternator and starter troubleshooting. For additional electricaltroubleshooting information, see 600 Electrical System-General.
Special tools
4 Automotive digital multimeter
CAUTION-
Only use a digitalmultirneterwhen testingautomotive electri-
I )
cal components.
4 Closed-circuit current measurement adaptor
(Tool No. BMW 61 2 300)
Engine electrical system
The alternator and starter are wired directly to the battery. To prevent accidental shorts that might blow a fuse or damage wires and electrical components,always disconnect the negative (-)battery cable before working on the electrical system.
Various versions of alternators,voltage regulators, starters, and batteries are used in E39 cars. Replacecomponents according to the original equipment specification.
@ TOfuse & relay panel
point
002125~1
Battery, Starter, ~lternatorl
Battery Safety Terminal
A Battery Safety Terminal (BST) controlled by the Multiple Restraint System (MRS) control unit was introduced for model year 1998 vehicles. The system will disconnect electrical power to the engine compartment in the event of a significant impact. The MRS system fires an encapsulated pyrotechnic device in the positive (+) battery terminal that disconnects power to the engine compartment, but maintains power to the exterior lights and interior of the vehicle.
Table a. Battery, alternator and starter troubleshooting
Symptom
Engine does not crank
Engine cranks slowly or not at all, solenoid clicits when starter is operated.
Probable cause
Fault in immobilizer system (EWS)
CleBatteryn-
cables loose, dirty or corroded.
Battery discharged.
Battery to body ground cable in trunk loose, dirty or corroded
Poor connection at starter motor terminal 30.
/Starter motor or solenoid faulty.
I
Battery will not stay charged more than a few days.
IShort circuit draining battery.
Short driving trips and high electrical drain on charging system does not allow battery to
recharge.
.
Drive belt@)loose, worn or damaged.
I ~ a t t efaultyr~.
IBattery cables loose, dirty or corroded.
IAlternator or voltage regulator faulty.
Corrective action
Try another ignition key. If problem persists, contact your authorized BMW dealer.
or replace cables. See 020 ~aintenance.
Charge battery and test. Replace if necessary.
inspect ground cable. Clean, tighten or replace if necessary.
Checlc connections, test for voltage at starter. Test for
voltage at neutral safety or clutch interloclc switch.
1 -
l ~ e sstarter.
I
l ~ e sfort excessive current drain with everything
Evaluate driving style. Where possible, reduce electrical consumption when malting short trips.
I
Inspect or replace ribbed belt@).See 020 Maintenance.
/Test battery and replace if necessary.
Iclean or replace cables. See 020 Maintenance.
/Test alternator and voltage regulator.
.-. .
Battery, Starter, Alternator
Warnings and cautions
WARNING -
Wear goggles, rubber gloves, and a rubber apron when working around the battery or battery acid (electrolyte).
Battery acid contains sulfuric acid and can cause skin irritation and burning. If acid is spilled on your skin or clothing, flush the area at once with large quantities of water. If electrolytegets into your eyes, flush them with large quantities of clean water for several minutes and call a physician.
Batteries that are being charged or are fully charged give off explosive hydrogen gas. Keep sparks and open flames away. Do not smoke.
CAUTIOI\C
Only use a digital multimeter when testing automotiveelectrical components.
.If a repair procedure specifies disconnecting the battery, follow the instruction for safety reasons.
Prior to disconnecting the battery, read the battery disconnection cautions in 001 General Cautions and
Warnings.
Models with MS43 engine management: Allow at least 3 minutes to elapse after turning ignition ley to OFFposition before disconnecting battery. This willallow sumcient tinie to complete the DMJL (fuel tank pressure) test
* Disconnectingthe battery cables may erase fault codes stored in ECM memory.
Always disconnect the negative (-)battery cable first and reconnect it last. Cover the battery post with an insulating material whenever the cable is removed.
Do not disconnect battery, alternator or starter wires while the engine is running.
0 Never reverse the battery cables. Even a momentary wrong connection can damage the alternator or other electrical components.
Do not depend on the color of insulation to tell battery positive and negative cables apart. Label cables before removing.
The slide-tilt sunroof may fail to function properly after disconnecting and reconnecting the battery. Reinitialize sunroof as described in 540 Sunroof.
