Factory Repair Manual for the BMW N55 engine (inline 6-cylinder, 3.0L TwinPower Turbo). Includes detailed step-by-step instructions for maintenance, diagnostics, and overhaul. Contains comprehensive data on the Valvetronic (Variable Valve Lift), VANOS (Variable Camshaft Timing), fuel injection, and single-flow twin-scroll turbocharger.
BMW F30 335i Engine (N55)
| Password For Document: bimmer-service.com | |
| Engine. Cylinder head with lid | Download |
| Oil sump. Case Covers. Crankshaft and Bearings | Download |
| Flywheel. Vibration damper | Download |
| Connecting Rods and Bearings. Pistons with Rings and Pins | Download |
| Drive belt with tensioning and deflecting element | Download |
| Camshaft. Rocker arm with bearing. Valves with springs | Download |
| Variable camshaft control. Variable valve gear | Download |
| Oil supply. Oil pump with strainer and motor. Oil filters and lines | Download |
| Coolant pump with drive. Thermostat and engine-proof coolant lines | Download |
| Intake manifold. Charger with control | Download |
| Vacuum pump. CO adjustment, oxygen sensor | Download |
| Engine Electrical System | Download |
| Fuel preparation and control. Fuel supply | Download |
| Cooling | Download |
| Exhaust system | Download |
| Engine and transmission mounting | Download |
BMW F07 535i N55B30M0
N55B30M0 (F07/535i) N54B30O0 (E71/X6 xDrive35i)
| Password For Document: bimmer-service.com | |
| Introduction. Engine Components/Systems Overview. Technical Data | Download |
| Engine Components Workshop Manual | Download |
| Circuit Diagram. Engine Cooling Circuit Diagram | Download |
| Digital Motor Electronics (DME/ECM) | Download |
| Service Information. Cylinder Head. Fuel Injectors. Ignition Coils | Download |
N55 (3.0L TwinPower Turbo) Typical Malfunctions
1. Cooling System Problems
Electric Water Pump: This is one of the most common and well-known problems with the N55. The electric pump has a limited lifespan and can fail without warning, causing the engine to quickly overheat.
Thermostat: Like the water pump, the electronically controlled thermostat can fail, often sticking in the closed position, which also causes overheating.
2. Oil Leaks (Oil Filter and Gaskets)
Oil Filter Housing Gasket (OFHG): A classic BMW problem. This gasket hardens over time from high temperatures and begins to leak. Leaking oil can leak onto the drive belt, causing it to slip and become caught under the front crankshaft oil seal (a very serious and expensive failure).
Valve Cover Gasket: Due to high temperatures, the plastic cover and gasket become unsealed, leading to oil leaks around the perimeter.
Oil Pan Gasket: Oil leaks from the oil pan gasket are also quite common.
3. Intake and Turbocharger Issues
PCV Valve / Valve Cover: The PCV system is integrated into the valve cover. A failed valve or its diaphragm leads to increased oil consumption, vacuum leaks, and possible whistling.
Turbocharger (Single Twin-Scroll): While generally reliable, over time, problems with the actuator (wastegate) can develop, causing overboost or underboost and boost errors. Oil leaks are also possible at high mileage.
4. Fuel and Ignition System Issues
Ignition Coils and Spark Plugs: The engine is sensitive to ignition conditions, especially with chip tuning. Worn spark plugs or failed coils cause misfires, loss of power, and limp home mode.
Fuel Injectors: Although the N55 uses more reliable solenoid injectors (as opposed to the piezoelectric ones on early N54s), they can leak or fail over time, requiring replacement.
5. VANOS and Valvetronic Issues
VANOS Solenoids: Over time, the solenoids that control the valve timing (VANOS) can become dirty or fail. This leads to unstable engine operation, fluctuating RPM, and timing errors.
Valvetronic Camshaft Sensor: The N55 is equipped with a variable valve lift system (Valvetronic). Failure of the eccentric shaft sensor or the Valvetronic servo itself may result in the engine running in limp mode (using only the throttle valve).
Common Engine OBD-II Trouble Codes
P0100–P0104 — Mass or Volume Air Flow Circuit
Issues with the MAF (Mass Air Flow) sensor, often due to contamination or air leaks.
P0110–P0114 — Intake Air Temperature Sensor Circuit
Incorrect readings from the IAT sensor, affecting air/fuel mixture.
P0120–P0124 — Throttle/Pedal Position Sensor/Switch Circuit
Problems with the throttle position sensor (TPS), causing unstable idle or acceleration.
P0170–P0175 — Fuel Trim Malfunction (Bank 1/2)
Indicates the air-fuel ratio is too rich or too lean; often caused by vacuum leaks, fuel pressure, or injector issues.
P0200–P0204 — Injector Circuit Malfunction
Fault in the electrical circuit or control of the fuel injector.
P0300 — Random/Multiple Cylinder Misfire Detected
General misfire; could be caused by spark plugs, coils, or fuel delivery.
P0301–P0306 — Cylinder-Specific Misfires
Misfire detected in a specific cylinder (e.g., P0302 = Cylinder 2 misfire).
P0400–P0409 — Exhaust Gas Recirculation (EGR) Flow Malfunction
EGR valve not functioning properly, leading to increased emissions.
P0420–P0430 — Catalyst System Efficiency Below Threshold (Bank 1/2)
Catalytic converter not performing efficiently; may indicate exhaust leaks or sensor issues.
P0440–P0455 — Evaporative Emission Control System (EVAP) Leak Detected
Loose gas cap, broken hoses, or faulty purge valve can trigger this.
P0500 — Vehicle Speed Sensor Malfunction
The ECM isn’t receiving a proper signal from the speed sensor.
P0600–P0606 — PCM/ECM Communication or Internal Fault
Issues within the vehicle’s control module (software or hardware).
P0700 — Transmission Control System (MIL Request)
Transmission issue detected; often requires separate TCM diagnostics.