01 Brake Fluid Leaks: Causes, Locations, and Solutions • 02 ECU Tuning: Benefits, Risks, and the Tuning Process • 03 Fuel Efficiency Unleashed: 10 Hacks for Smart Driving and L… • 04 How to Reset a Car Computer After Replacing the Battery • 05 How Often Should You Drive Your Car to Keep It in Good Shap… • 06 This Maintenance Myth Is Turning Small Car Issues Into Huge… • 07 Troubleshooting Your Refrigerator: A Comprehensive Guide • 08 Charging Anxiety vs. Green Future: Why Americans Aren't Buy… • 09 8 Factors That Contribute to High Fuel Consumption • 10 Prevent Disaster: The Ultimate Guide to Installing Cotter (… •

DTC codes / BMW codes / P1352

P1352 · BMWMisfire During Start Cylinder 6

P1352 on BMW vehicles means the engine control module detected a misfire specifically on cylinder 6 during the engine start sequence, before normal closed-loop operation begins. The computer monitors crankshaft speed fluctuations during cranking and the first few combustion events, and flags this code when cylinder 6 fails to contribute its expected power. This is a start-specific misfire code, not a general running misfire, which narrows the diagnostic path considerably.

SystemPowertrain
Code typeBMW specific
SeverityMedium
Fix difficultyIntermediate
AreaIgnition system and misfire

Symptoms you may notice

  • Rough or stumbling idle immediately after cold start, often smoothing out once the engine warms
  • Extended cranking time before the engine catches, especially on cold mornings
  • A flashing or steady check engine light shortly after startup
  • Audible popping or uneven exhaust note during the first few seconds of running
  • Occasional hard start or stall right after ignition, particularly in damp or cold weather
  • Often no symptoms besides the warning light when the misfire is intermittent and only logged during cranking

Common causes, most likely first

  1. Faulty or fouled spark plug on cylinder 6, especially with incorrect gap or wear beyond the service interval
  2. Failed ignition coil on cylinder 6 that breaks down under the higher load of cold-start enrichment
  3. Leaking or clogged fuel injector on cylinder 6 causing an incorrect air-fuel mixture during cranking
  4. Intake manifold gasket or vacuum leak near cylinder 6 that leans out the mixture only at low cranking speeds
  5. Low compression on cylinder 6 from worn rings, a leaking valve, or a head gasket issue that shows up mainly when cold
  6. Carbon buildup on the intake valves of cylinder 6, common on direct-injection BMW engines, disrupting cold-start mixture
  7. Engine control module software or adaptation values that are out of range for cold-start fueling on that cylinder

How to diagnose and fix it

  1. Scan all BMW-specific fault memory and freeze-frame data to confirm P1352 is current and not a stored history code from a previous repair
  2. Inspect the cylinder 6 spark plug for fouling, wear, and correct gap, and replace it if it does not meet BMW specification
  3. Swap the cylinder 6 ignition coil with a neighbouring cylinder and recheck for a misfire that follows the coil, confirming coil failure
  4. Perform a fuel injector balance test or swap injectors between cylinders to see if the start misfire moves with the injector
  5. Run a cold compression test and, if low, a cylinder leak-down test on cylinder 6 to rule out mechanical faults before parts replacement
  6. Smoke-test the intake system for vacuum leaks near cylinder 6 and check the intake manifold gasket for signs of leakage
  7. After repairs, clear adaptations and recheck cold-start behaviour over several key cycles to confirm the code does not return

Why cylinder 6 misfires only at startup

  • A P1352 that never appears once the engine is warm often points to a coil or plug that only fails under the rich, high-load conditions of cold-start cranking, so a hot-engine misfire test will miss it.
  • Technicians frequently replace all six coils when only cylinder 6 is flagged, but swapping the coil to another cylinder first proves the fault without unnecessary parts.
  • Direct-injection BMW engines can develop carbon deposits on the back of the intake valves that cause a cold-start-only misfire on one cylinder, which a standard fuel injector cleaner will not fix.
  • A weak battery or slow cranking speed can cause the engine control module to misjudge crankshaft speed fluctuations and set a false P1352, so always check battery health and cranking voltage before condemning ignition parts.
  • This code can be stored alongside fuel trim or camshaft correlation codes when a vacuum leak or timing issue affects cylinder 6 disproportionately at low engine speeds.

Can I keep driving with P1352?

You can usually drive the car short distances to a workshop, but avoid hard acceleration and long trips until the misfire is diagnosed, because unburned fuel from a persistent misfire can overheat and damage the catalytic converter. If the check engine light flashes or the engine runs very rough, stop driving and arrange a tow.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for BMW vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

Running on fumes Free guides aren't free to make. Top up the tank. Any amount, one time. Fuel the Garage