P0355 on 2007-2013 BMW M3: Ignition Coil E Circuit Malfunction Causes and Fixes

What's Unique About the 2007-2013 BMW M3

The E9x M3's S65 V8 is a high-revving, naturally aspirated engine derived from the S85 V10. It uses a sensitive 'ionic current' knock detection system that sends a small electrical signal through the spark plug to monitor combustion. This makes using the correct OEM-spec NGK spark plugs (LKR8AP) critical for proper engine function, as aftermarket plugs can sometimes cause erroneous codes even when functioning perfectly. While ignition coil failure is common on many engines, the straightforward cylinder numbering (1-4 on passenger side, 5-8 on driver's side, front to back) makes locating the problem on the S65 relatively easy.

Symptoms You May Notice

• Check Engine Light is on (may be flashing)
• iDrive screen shows 'Engine Malfunction, Reduced Power' message
• Engine misfiring, shaking, or running rough, especially at idle.
🎬 Watch: Troubleshooting common causes for rough running and misfires.
• Noticeable loss of power and sluggish acceleration.
• Reduced fuel economy.
• Engine may hesitate or stumble under load.
• A 'pop-pop' sound from the exhaust during acceleration.

Most Likely Causes

1. Failed Ignition Coil on Cylinder #5 🔴 High Probability Ignition coils are wear-and-tear components that fail over time due to high heat cycles and electrical stress. This is the most common cause for a P0355 code on the S65 engine.
   How to confirm: Swap the ignition coil from cylinder #5 with another cylinder (e.g., cylinder #1 on the passenger side). Clear the codes and drive the car. If the code returns as P0351 ('Ignition Coil A'), the coil is faulty. Cylinder #5 is the front-most cylinder on the driver's side (US).
   Typical fix: Replace the faulty ignition coil. 🎬 Watch: Three different ways to replace your ignition coils. It is recommended to use a quality OEM brand like Bosch or Eldor. Many owners on forums report good experiences with Eldor coils, which became a later OEM supplier for many BMWs.
   Est. part cost: $40-$70
2. Worn or Fouled Spark Plug 🟡 Medium Probability The recommended replacement interval for spark plugs on the S65 engine is relatively short at ~37,000 miles. A worn or fouled plug can increase resistance in the secondary ignition circuit, which can over-stress the coil, causing this code or leading to premature coil failure.
   How to confirm: After moving the ignition coil and confirming the fault remains on cylinder #5 (P0355 returns), remove the spark plug. Inspect it for excessive wear, carbon or oil fouling, or damage to the electrode or ceramic insulator.
   Typical fix: Replace the spark plug. It's best practice to replace all 8 spark plugs 🎬 See this step-by-step guide for replacing S65 spark plugs. if they are near their service interval. Use only the specified NGK LKR8AP plugs due to the S65's ionic current system.
   Est. part cost: $15-$25 per plug
3. Damaged Wiring or Connector ⚪ Low Probability Engine heat and vibration can make the plastic connector for the ignition coil brittle over time, leading to cracks or a poor connection. The locking tab is especially prone to breaking. Wires can also become frayed or damaged.
   How to confirm: Visually inspect the wiring harness and 3-pin connector going to the ignition coil on cylinder #5. Check for cracks in the connector body, corrosion on the pins, or loose-fitting connections. Wiggle the connector with the engine running to see if it induces a misfire.
   Typical fix: Repair the damaged section of wire or replace the pigtail connector. The connector kit is available under part number 12527519996.
   Est. part cost: $10-$30 for a connector pigtail kit

Rare But Worth Checking

• Faulty DME (Engine Computer): This is very rare. The driver circuit within the DME that controls the ignition coil can fail. This should only be considered after all other possibilities (coil, plug, wiring) have been definitively ruled out through testing. A shop would need to perform advanced diagnostics, like checking the signal from the DME with an oscilloscope, to confirm this.

Diagnosis Steps

1. Read the trouble codes with an OBD-II scanner to confirm P0355 and any other related codes like P0305.
2. Identify cylinder #5. On a US-spec M3, this is the front-most cylinder on the driver's side bank (Bank 2).
3. Remove the plastic engine cover and acoustic foam to access the ignition coils.
4. Swap the ignition coil from cylinder #5 with the coil from another cylinder, for example, cylinder #1 (front-most on the passenger side). Mark the coils to keep track of them.
5. Clear the trouble codes with the scanner.
6. Start the engine and let it run for a minute, or take a short drive until the check engine light returns.
7. Re-scan for codes. If the code has changed to P0351 ('Ignition Coil A Circuit Malfunction'), the ignition coil you moved is faulty and needs to be replaced.
8. If the code P0355 returns, the problem is not the coil. The next step is to inspect and likely replace the spark plug in cylinder #5.
9. If the spark plug is new or in good condition, the final step is to carefully inspect the wiring and the 3-pin connector for cylinder #5's ignition coil for any damage, corrosion, or loose connections. The connector housing is part number 12527519996.

Parts You'll Likely Need

• Ignition Coil (OEM #12137841754) — This is the most common cause of a P0355 code, failing from heat and age.
  Trusted brands: BMW (Genuine), Bosch, Eldor, Delphi
  OEM price range: $60-$80
  Aftermarket price range: $40-$60
• Spark Plug (OEM #12120032273) — A required maintenance item with a ~37,000-mile service life. A worn plug can cause this fault or be discovered during diagnosis. The S65 requires a specific plug for its ionic current monitoring system.
  Trusted brands: NGK (LKR8AP)
  OEM price range: $20-$30
  Aftermarket price range: $15-$25
• Ignition Coil Connector Pigtail Kit (OEM #12527519996) — The plastic connector can become brittle from engine heat and crack, causing a poor connection. This kit is needed if the connector housing is damaged.
  Trusted brands: BMW (Genuine), Kostal (OEM manufacturer)
  OEM price range: $10-$20
  Aftermarket price range: $8-$15

Related Codes That Often Appear With This One

• P0305 — P0305 means 'Cylinder 5 Misfire Detected.' Since P0355 indicates an electrical fault in the ignition circuit for cylinder 5, a misfire is the direct result. You will almost always see P0305 alongside P0355.
• 2755 — This is a BMW-specific code for 'Ignition circuit cylinder 5'. It is the manufacturer-specific equivalent of the generic P0355 code and provides the same information. Note that some online lists may incorrectly associate 2755 with other cylinders or systems on different BMW engines.

Platform-Specific Known Issues

• source — A user on M3Post reported getting codes P0353 (Cylinder 3) and P0355 (Cylinder 5) simultaneously. After swapping coils from known good cylinders, the codes remained for cylinders 3 and 5, indicating the coils were not the issue. This points towards a wiring or, in very rare cases, a DME issue affecting multiple cylinders on the same bank.

Mechanic-Grade Diagnostic Values

• Ignition Coil Primary Winding Resistance — expected: Approximately 0.8 to 0.9 Ohms (Ω). Failure: A reading of infinite resistance (open circuit) or zero resistance (short circuit). However, resistance tests may not identify coils with internal insulation breakdown that only fails under load.
• Ignition Coil Connector Pin Voltages (Key On, Engine Off) — expected: Pin 1 (DME Trigger Signal): 0V. Pin 2 (Ground): 0V. Pin 3 (Power Supply): ~12V (Battery Voltage).. Failure: No voltage at Pin 3 indicates a power supply issue. Voltage present at Pin 1 with key on suggests a short or DME driver issue.

Hidden / Shadow Codes Worth Checking

• 0x2755: DME: Ignition circuit, cylinder 5. This is the direct BMW-specific hexadecimal code for the P0355 fault. (see via BMW-specific diagnostic software such as ISTA/D or advanced aftermarket scanners that can read manufacturer codes.)

Scan Tool Commands That Help

• ISTA/D: Call up ECU functions -> Diagnosis scan -> Smooth running values — While ISTA cannot directly test coil resistance, monitoring the 'smooth running values' can help identify which cylinder is misfiring or running rough, even without a specific misfire code. This helps confirm the affected cylinder before swapping parts.
• ISTA/D: Calculate Test Plan — After reading the fault memory (which will show 2755), ISTA will generate a guided diagnostic plan. For this fault, it will typically instruct the technician to check the power supply to the coil, inspect the wiring, and then suggest swapping the coil with another cylinder, automating the standard diagnostic procedure.

Wiring & Ground Locations

• Ignition Coil Connector (X60102 for DME) — Directly on top of each ignition coil, under the plastic engine covers.. This 3-pin connector provides power, ground, and the trigger signal from the DME. A loose connection, corrosion on the pins, or a broken locking tab can directly cause a P0355 fault. The pinout is: Pin 1 - Signal from DME, Pin 2 - Ground, Pin 3 - 12V Power.
• Engine Ground Strap — A braided metal strap connecting the engine block to the vehicle's chassis. On the E90 chassis, a key ground strap is located across the driver's side engine mount.. While not a direct cause of a single-cylinder fault, a corroded or loose main engine ground can create intermittent and difficult-to-diagnose electrical issues across the ignition system. If multiple, seemingly random electrical faults are present, inspecting the main ground straps is a wise step.
• Ionic Current Control Module — There are two modules, one on each valve cover, underneath the main plastic engine covers. Each module serves one bank of cylinders (Bank 1: 1-4, Bank 2: 5-8).. This module processes the ionic current signal for knock detection. A failure in this module can cause misfires and ignition-related faults that may be misdiagnosed as a bad coil or plug. Swapping the modules between banks is a valid diagnostic step if a fault persists on one bank after changing coils and plugs.

Real Owner Repair Stories

• M3Post user 'lynn' (2008-2013 BMW E92 M3) — Limp mode on startup, rough running, codes 2754 (Ignition, cylinder 2) and 2755 (Ignition, cylinder 3).
  ❌ Tried (didn't work) Clearing codes., Replacing battery., Checking grounding bolts on valve covers.
  ✅ What actually fixed it The user had recently replaced the valve cover gaskets and spark plug tubes with aftermarket (URO brand) parts. The rubber grommets on the new spark plug tubes failed, allowing oil to leak into the spark plug wells for cylinders 2 and 3, shorting out the spark. The final fix was to replace the faulty aftermarket spark plug tubes with genuine BMW parts.
• M3Post user 'WRichieX' (on a related N54 engine, but illustrates DME failure) (2007 BMW 335i) — Car ran terribly after replacing spark plugs, threw code 30BB (DME internal fault).
  ❌ Tried (didn't work) Replacing spark plugs.
  ✅ What actually fixed it The MOSFET driver for injector #5 on the DME circuit board had failed. A friend with soldering skills replaced the failed MOSFET on the board. After the DME repair, the car ran better but not perfectly. Replacing all the ignition coils brought the car back to running like new, suggesting the DME failure may have damaged a coil.

OEM Part Supersession History

• 12137838388 → 12137841754 — Standard part evolution and supplier changes. The S65 originally used Bosch coils.
  Heads up: The parts are fully interchangeable. However, many owners and specialists have noted that later OEM supplier Eldor (used on other BMW models) produced more robust coils than the original Bosch units. While not a direct supersession for the S65, some owners choose to use compatible Eldor coils from other models as a perceived upgrade.

Diagnostic Flowchart

Other Known Issues on This Vehicle

Issues unrelated to this code that are worth knowing about as an owner of this generation:

• Rod Bearing Wear 🔴 High — A well-known and highly discussed issue. Considered a preventative maintenance item by many owners, often replaced between 60,000-80,000 miles. Failure can be catastrophic to the engine. (Ref: No official recall, but the subject of a class-action lawsuit (Urena v. BMW of North America LLC).)
• Throttle Body Actuator Failure 🔴 High — Very common failure item. The internal plastic gears wear out or the electronics fail, causing limp mode and fault codes (e.g., 2B15, 2B16). Can fail at various mileages, typically without warning.
• Idle Control Valve (ICV) Failure 🟠 Medium — Common on higher-mileage cars. The valve can get stuck or the motor fails, causing a rough, surging, or unstable idle and potentially limp mode. (Ref: A past Service Bulletin (13-05-08) was issued for this part, though it may have been for an earlier version of the component.)
• Valve Cover Gasket Leaks 🟡 Low — Common oil leak point as the vehicle ages. The gaskets become hard and brittle, and the magnesium valve covers can sometimes warp, causing oil to leak onto the exhaust or into the spark plug wells.

Used vs. New Parts: Buying Guide for This Vehicle

When a used part is the smart pick: For this repair, used parts are generally not recommended for the primary failure components. A used ignition coil or spark plug carries the same risk of failure as the part being replaced. However, a used wiring harness connector (pigtail) or a used Ionic Current Control Module from a reputable salvage yard can be a cost-effective option if confirmed to be in good condition.

Donor-vehicle mileage cap: roughly under 60000 miles for the part to have meaningful remaining life.

What to inspect on the donor part:

• For a used Ionic Module: Check the part number to ensure it's the correct revision. Inspect the housing for cracks or signs of heat damage. Ensure connector pins are clean and not corroded.
• For a used connector pigtail: Inspect the plastic for brittleness or cracks. Ensure the locking tab is intact and functional. Check that there is ample wire length for splicing.

OEM-only on this vehicle (don't cheap out):

• Spark Plugs: The S65's ionic current system is sensitive. Only use the specified OEM NGK LKR8AP plugs to avoid diagnostic headaches.
• Ignition Coils: While aftermarket options exist, the cost savings are minimal and many forum users report immediate misfires with non-OEM brands. Stick to Genuine BMW or a known OEM supplier like Bosch or Eldor.

Aftermarket brands forum-validated for this vehicle:

• Bosch (Often the original OEM supplier)
• Eldor (A later OEM supplier for BMW, widely considered very reliable)
• Delphi (Another OEM supplier)

Brands owners have reported issues with on this vehicle:

• Generic, unbranded ignition coils from online marketplaces. Forum threads frequently mention issues with cheap aftermarket coils causing immediate misfires on the S65 engine.

Real Owner Stories

Aggregated from forums and TSBs cited above. Mileages and costs reflect what owners reported in those sources.

Related OBD-II Codes

• P0305 — Misfire code for cylinder #5. P0355 indicates a fault in the ignition coil's primary circuit, which directly causes the cylinder not to fire, resulting in a P0305 misfire code.
• P0351 — Ignition Coil 'A' (Cylinder 1) Primary/Secondary Circuit Malfunction. This code is expected to appear during diagnosis if a faulty coil from cylinder #5 is swapped to cylinder #1 to confirm the failure.
• P0353 — Ignition Coil 'C' (Cylinder 3) Primary/Secondary Circuit Malfunction. Can appear with P0355, suggesting a broader issue affecting multiple cylinders on the same bank, such as a wiring harness problem or a rare DME fault.
• P035X — A generic representation for any code from P0351-P0358. The final digit corresponds to the cylinder number. Multiple P035x codes often point away from a single coil failure and towards a wiring or DME issue.
• 2B15 — BMW-specific code for 'Throttle-valve actuator control monitor Bank 1'. While not directly related to the ignition system, it is a very common failure on the S65 that produces the same 'Engine Malfunction, Reduced Power' message as P0355.
• 2B16 — BMW-specific code for 'Throttle-valve actuator control monitor Bank 2'. Similar to 2B15, this is a common cause for limp mode on the S65 and can be confused with ignition issues due to the identical warning message on the iDrive screen.

Frequently Asked Questions