BMW 525i, 528i, 530i, 540i, Sedan, Sport Wagon (E39, 5 Series) Repair Manual 1997-2003

• BMW 525i
• BMW 528i
• BMW 530i
• BMW 540i

• VOLUME ONE: General Maintenance | Engine | Transmission | Suspension, Steering and Brakes | Body | Equipment and Accessories
  
  
• VOLUME TWO: Electrical System | Electrical Wiring Diagrams

• 6-cylinder engines: M52 | M52 TU | M54
• V-8 engines: M62 | M62 TU

ENGINE COOLANT TEMPERATURE (ECT) SENSOR, TESTING AND REPLACING

The ECT sensor is located below cylinder 6 intake port at the rear of the engine (see diagram 1).

The ECT sensor is a dual temperature sensor. One circuit provides coolant temperature information to the ECM while the other circuit provides coolant temperature information to the instrument cluster.

The ECM determines the correct ignition timing and air/fuel mixture required for the engine temperature by monitoring an applied voltage (5 vdc) to the sensor. The voltage drop across the sensor varies as the coolant temperature (sensor resistance) changes.

NOTE: The ECT sensor is an NTC (negative temperature coefficient) type sensor. In other words, as the temperature rises, resistance through the sensor decreases.

If the ETC sensor input is faulty or non-plausible, the MIL is illuminated when OBD II fault criteria are exceeded. The ECM assumes a substitute value (80 degrees C/ 176 degrees F) to maintain engine operation. The ignition timing is set to a conservative/safe basic setting.

• Remove intake manifold to access ECT sensor on the M52 TU and the M54 engines. See 113 Cylinder Head Removal and Installation



• Check ECT sensor resistance using a multimeter at sensor terminals

TRUNK LID ADJUSTING

• Truck lid must be parallel to both side panels and should be mounted flush with body side panels (see arrows). Lid fit tolerance is +/- 1mm (0.04 in).



• Raise trunk lid and support in open position.



• Turn trunk lid detent buffers in (see photo).



• Remove trunk strut retaining clip (see arrow) and disconnect struts.


WARNING! Make sure to support trunk lid before removing struts.


• Loosen bolts at left and right trunk hinges fasteners (see arrows) to point where lid can be moved.



• Remove plastic cover from lower trunk lock. Loosen lock bolts (see arrows) until lock assembly can be moved.


CAUTION! Before locking trunk lid, check that trunk lid is not able to damage the body or rear window.


• Carefully close trunk lid and check side gaps (see arrows). Minimum gap is 0.5 mm (0.02 in).



1. Adjust to fit side body panels.
2. Open trunk lid. Be careful not to alter adjustments.
3. Tighten lower trunk lock fasteners.
4. Close trunk lid and check adjustments.
5. Repeat process if necessary.

• Important Safety Notice
• General Data and Maintenance
• Warnings and Cautions
• Vehicle Identification and VIN Decoder
• Engine
• Engine Removal and Installation
• Cylinder Head Removal and Installation
• Cylinder Head and Valvetrain
• Camshaft Timing Chain
• Lubrication System
• Ignition System
• Battery, Starter, Alternator
• Fuel Injection
• Radiator and Cooling System
• Transmission
• Clutch
• Manual Transmission
• Sequential Manual Gearbox (SMG)
• Automatic Transmission
• Gearshift Linkage
• Transfer Case
• Suspension, Steering and Brakes
• Body
• Body Equipment
• Seats
• Sunroof
• Convertible Top
• Electrical System
• Electrical Component Locations
• Instruments
• Heating and Air-conditioning
• Radio
• Equipment and Accessories
• Airbag System (SRS)
• Electrical Wiring Diagrams
• On-Board Diagnostics