The largest online repair guide library for every car

About us
Contact support
FAQ
Sign up
Sign in

2016 Cooper S Check Engine Light with Rough Idle and Misfires - P0301 & P0171

0

Mike T. · rep 0 · May 25, 4:55 AM · 1 replies · solved · Question

Vehicle: 2016 Mini Cooper S Hardtop 2-Door

Hey everyone,

My 2016 Mini Cooper S Hardtop 2-Door has been acting up lately. The Check Engine Light came on, and the car feels really rough at idle, almost like it's going to stall. When I accelerate, there's a noticeable lack of power and it feels like it's misfiring.

I hooked up my OBD-II scanner and pulled a couple of codes: P0301 (Cylinder 1 Misfire Detected) and P0171 (System Too Lean Bank 1). I'm not sure if these are related or what the best approach is to start diagnosing this.

Any ideas on where to begin? Could it be spark plugs, coils, or something more serious?

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 25, 4:55 AM

0

ClearTheCode admin answer:

It sounds like your 2016 Mini Cooper S is experiencing common issues related to misfires and a lean condition. The P0301 (Cylinder 1 Misfire) and P0171 (System Too Lean) codes often go hand-in-hand.

Here's a diagnostic approach:

  1. Check Spark Plugs and Ignition Coils:

    • Start by inspecting the spark plug in cylinder 1. Look for signs of fouling, wear, or damage. If it looks bad, consider replacing all spark plugs, especially if they haven't been changed in a while.
    • Swap the ignition coil from cylinder 1 with a coil from another cylinder (e.g., cylinder 2). Clear the codes and drive the car. If the misfire code moves to cylinder 2 (P0302), you've identified a bad coil.

  2. Inspect for Vacuum Leaks:

    • A lean condition (P0171) is frequently caused by unmetered air entering the engine. Carefully check all vacuum lines, intake manifold gaskets, and PCV valve/hoses for cracks or disconnections. A smoke test can be very effective here.

  3. Fuel System Check:

    • A clogged fuel injector in cylinder 1 could cause both a misfire and contribute to a lean condition. You might also have a failing fuel pump or a clogged fuel filter, though P0171 is more commonly a vacuum leak.

  4. Oxygen Sensor/MAF Sensor:

    • While less likely to cause a specific cylinder misfire, a faulty upstream oxygen sensor or Mass Air Flow (MAF) sensor could contribute to the P0171 lean code by providing incorrect air/fuel mixture data to the ECU.

When to See a Shop:

If after checking spark plugs, coils, and performing a thorough visual inspection for vacuum leaks, the problem persists, it's time to visit a qualified Mini specialist. They have advanced diagnostic tools to perform fuel pressure tests, injector flow tests, and more detailed sensor diagnostics. Ignoring these issues can lead to catalytic converter damage or further engine problems.

Menu

Help & account