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Loss of Power & CEL on 2018 440i - Charge Pipe?

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Mike T. · rep 0 · May 25, 2:58 AM · 1 replies · solved · Question

Vehicle: 2018 BMW 440i Gran Coupe

Hey guys,

My 2018 BMW 440i Gran Coupe (B58 engine) just threw a Check Engine Light and went into limp mode yesterday. I was accelerating onto the highway, and suddenly felt a massive loss of power, almost like the turbo wasn't working at all. There was also a loud whooshing sound from the engine bay right before it happened.

I pulled over, restarted the car, and while the CEL stayed on, the power seemed to be back, but it still feels a bit sluggish. I scanned it with my OBD-II reader, and got codes P0299 (Turbo/Super Charger Underboost) and P0101 (Mass Air Flow Sensor Performance Problem).

Could this be the infamous charge pipe failure? I know it's a common issue on N55s, but I thought the B58 was better. Any B58 owners experience this? What's the typical fix, and is it safe to drive to the shop?

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 25, 2:58 AM

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ClearTheCode admin answer:

Your symptoms and the specific OBD codes you've pulled (P0299 and P0101) are highly indicative of a charge pipe failure on your 2018 BMW 440i with the B58 engine. While the B58's charge pipe is generally more robust than the N55's, it's not entirely immune to failure, especially as the plastic ages and becomes brittle under heat and pressure.

  1. Symptoms Match: The sudden loss of power during acceleration, the loud whooshing sound, and the Check Engine Light with underboost codes (P0299) are classic signs of a cracked or burst charge pipe. The P0101 code can also appear due to the unmetered air entering the system after the MAF sensor, confusing the engine's air-fuel mixture calculations.

  2. Causes: The charge pipe, which connects the intercooler to the throttle body, is subjected to significant pressure from the turbocharger. Over time, the plastic material can weaken and crack, especially at stress points or where clamps are located. This creates a boost leak, causing the engine to lose power as it can't maintain target boost levels.

  3. When to See a Shop: It is generally not recommended to drive extensively with a boost leak. While you might regain some power after restarting, the engine is operating inefficiently, and the air-fuel mixture will be off. This can put added stress on other components and potentially lead to further issues. Get it to a reputable BMW specialist as soon as possible.

  4. Diagnostics: A mechanic will visually inspect the charge pipe for cracks, especially near the throttle body and intercooler connections. They might also perform a smoke test to precisely locate the leak. The fix is straightforward: replace the failed charge pipe.

  5. Repair Options: Many owners opt to replace the OEM plastic charge pipe with an aftermarket aluminum version. Aluminum charge pipes are significantly more durable and less prone to failure, offering a long-term solution. This is a common upgrade for both stock and tuned B58 engines.

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