Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2021 BMW M340iFACTORY OEM SERVICE PROCEDURE
Engine Electrical System -- Repair (G20) (2 Of 2)
- 12 51 Engine Wiring Harness
- 12 51 210 Replacing the wiring harness section for injectors and ignition coils (330i and 330i xDrive)
- 12 51 215 Replace the wiring harness section for the Valvetronic servomotor (330i and 330i xDrive)
- 12 51 235 Remove and install/replace Module 1, sensor system engine wiring (330i)
- 12 51 240 Remove and install/replace Module 2, sensor system engine wiring (330i and 330i xDrive)
- 12 51 245 Remove and install/replace transmission module engine wiring (330i)
- 12 51 235 Remove and install/replace Module 1, sensor system engine wiring (330i xDrive)
- 12 51 245 Remove and install/replace transmission module engine wiring (330i xDrive)
- 12 51 210 Replacing the wiring harness section for injectors and ignition coils (330e PHEV and 330e xDrive PHEV)
- 12 51 215 Replace wiring harness section for Valvetronic servomotor (330e PHEV and 330e xDrive PHEV)
- 12 51 235 Remove and install/replace Module 1, sensor system engine wiring (330e PHEV)
- 12 51 240 Remove and install/replace Module 2, sensor system engine wiring (330e PHEV and 330e xDrive PHEV)
- 12 51 245 Remove and install/replace transmission module engine wiring (330e PHEV)
- 12 51 235 Remove and install/replace Module 1, sensor system engine wiring (330e xDrive PHEV)
- 12 51 245 Remove and install/replace transmission module engine wiring (330e xDrive PHEV)
- 12 51 210 Replacing the wiring harness section for injectors and ignition coils (M340i and M340i xDrive)
- 12 51 210 Replacing the wiring harness section for injectors and ignition coils (M340i and M340i xDrive 48V)
- 12 51 235 Remove and install/replace Module 1, sensor system engine wiring (M340i)
- 12 51 235 Remove and install/replace Module 1, sensor system engine wiring (M340i 48V)
- 12 51 240 Remove and install/replace Module 2, sensor system engine wiring (M340i)
- 12 51 240 Remove and install/replace Module 2, sensor system engine wiring (M340i 48V)
- 12 51 245 Remove and install/replace transmission module engine wiring (M340i)
- 12 51 245 Remove and install/replace transmission module engine wiring (M340i 48V)
- 12 51 235 Remove and install/replace Module 1, sensor system engine wiring (M340i xDrive)
- 12 51 235 Remove and install/replace Module 1, sensor system engine wiring (M340i xDrive 48V)
- 12 51 240 Remove and install/replace Module 2, sensor system engine wiring (M340i xDrive)
- 12 51 240 Remove and install/replace Module 2, sensor system engine wiring (M340i xDrive 48V)
- 12 51 245 Remove and install/replace transmission module engine wiring (M340i xDrive)
- 12 51 245 Remove and install/replace transmission module engine wiring (M340i xDrive 48V)
- 12 61 Oil Pressure, Oil Temp, Oil Level Check
- 12 61 280 Removing and installing/replacing oil pressure switch (330i and 330i xDrive)
- 12 61 285 Replacing engine oil level sensor (330i)
- 12 61 285 Replacing engine oil level sensor (330i xDrive)
- 12 61 280 Removing and installing/replacing oil pressure switch (330e PHEV and 330e xDrive PHEV)
- 12 61 285 Replacing engine oil level sensor (330e PHEV)
- 12 61 285 Replacing engine oil level sensor (330e xDrive PHEV)
- 12 61 280 Removing and installing/replacing oil pressure switch (M340i and M340i xDrive)
- 12 61 285 Replacing the oil level sensor for engine oil (M340i)
- 12 61 285 Replacing engine oil level sensor (M340i xDrive)
- 12 63 Switch And Relay
- 12 63 586 Replacing power distribution box (after vehicle diagnosis) (330i, 330i xDrive, M340i and M340i xDrive)
- 12 63 586 Replacing power distribution box (after vehicle diagnosis) (330e PHEV and 330e xDrive PHEV)
- 12 63 586 Replacing power distribution box (after vehicle diagnosis) (M340i and M340i xDrive)
- 12 90 E-Box
- 12 90 150 Remove and install/replace control unit box (330i and 330i xDrive)
- 12 90 150 Remove and install/replace control unit box (330e PHEV and 330e xDrive PHEV)
- 12 90 150 Remove and install/replace control unit box (M340i and M340i xDrive)
- 12 90 150 Remove and install/replace control unit box (M340i and M340i xDrive 48V)
Factory Service Tools
Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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