BMW P0301 Code — Cylinder 1 Misfire (Advanced Diagnosis and Fix)

The P0301 code on your BMW indicates a misfire in cylinder 1.


What It Means

The air-fuel mixture in cylinder 1 is not burning properly.

👉 Result:

  • engine shaking
  • power loss
  • increased fuel consumption

Common Causes

1. Spark Plug


2. Ignition Coil

https://images.openai.com/static-rsc-4/Ii3-_rYl3dtSS7lWH0hZHK54-PLoZm-y4_ZQZ7sb4qFJqnzTYArof_f_LMaULrHO1pL-ost5YwnxPc9ojRHzyC5b2X0unCH5RBW7_O9RzHDXlgmDZ8Jsqx4-4GduA6M9kwwt70OekuTamHAwam4EdceGzUPEH3VgofwFeBxW7yaZ5BgzBIP00-zbypPuZQGJ?purpose=fullsize
https://images.openai.com/static-rsc-4/mUF5irjIyGXx4415mTBfnIBwbTBVQh8PJTFP4xkkkJK-S62TEPkNCtSo7wN4Jeg6HYvP7K9NqqoXUzpTpmqKCPlYaxoAurhd6i2JzbmlN9GtxNxGt5XFFc3m4q7sdHPwaBFHorK_Rykb18Hwxqw2wFEjTaWFOrn-u22EQRlubcBaZL2kzkm5drlmUvk7z9zK?purpose=fullsize


3. Fuel Injector

  • clogged
  • leaking

4. Vacuum Leak

  • intake leak

5. Low Compression

  • valves
  • piston rings

DIAGNOSIS

1. Coil Swap Test (BEST)

  • swap coil
  • check if error moves

2. Spark Plug Inspection

  • check wear
  • replace if needed

3. Injector Test

https://images.openai.com/static-rsc-4/uWT-993pINih74LZHhfn_IFooGTkVNkw199lnAtchq0llOnLdcCwa2WvuSp1eBdd4XcIxOcbCnEwdt8W2MSIF0wNaeDn7m8TECjdjynwj8l0UvWYV7ntsFt3cdP7xmXPg5euN_MJez5N-mAT2pAZt-wjCJEGjEP4GAAJ7BMlEhDJmpnTs3DgzZM8xm0EsH8-?purpose=fullsize
https://images.openai.com/static-rsc-4/sOzRdI4RJ94luE12EpKGw6Bxu00JQvtNp99RtjthIXNTccJ4MlLzNu10j2tAV5FnqcYjqnPb135sJh7B4VUF2SpSdZRJdBc6jAQunO-S-tnk4RZ8H-etvhSv2JiV_HbKb2c1FgsKbtS4q3E-5OW74mvkFhlh0ETVaCXl2mfAwzs-xBgDhBgL9cqbhaeweYrG?purpose=fullsize

  • resistance ~12–16 ohms

4. Compression Test

https://images.openai.com/static-rsc-4/R6E5RnngGecNGhdut61p8l_WeVz90TseNbGlNq3Qxtdl5Hk-cS3S_kGvexVytqTmVtJ3B9t0_-dmWz3AwMkU93L-BQNLCEPKRTWfFPegzRebh65CrHfMqDcpFooJzQUazON7oPxL3RklRD-aVjG9jRBqUZuDPlO5mG9vA7c_3stOnSxV0boNvmnSDI_zZtZK?purpose=fullsize

  • ~10–14 bar

5. OBD2 Data

  • misfire counter

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