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DTC codes / Nissan codes / P1202

P1202 · NissanCylinder 2 Misfire

P1202 on Nissan vehicles means the engine control module (ECM) has detected a misfire specifically on cylinder 2, usually by monitoring crankshaft speed fluctuations that occur when that cylinder fails to contribute power evenly. The ECM sets this code when the misfire count for cylinder 2 exceeds a calibrated threshold, which can range from a single hard misfire event to a recurring pattern over multiple drive cycles.

SystemPowertrain
Code typeNissan specific
SeverityMedium
Fix difficultyIntermediate
AreaFuel and air metering (injector circuits)

Symptoms you may notice

  • Check engine light illuminated, often steady but sometimes flashing if the misfire is severe enough to risk catalytic converter damage
  • Noticeable engine shake or vibration at idle that may smooth out at higher RPM
  • Rough running or hesitation during acceleration, particularly under load
  • A distinct popping or sputtering sound from the exhaust, especially on cold start
  • Often no symptoms besides the warning light when the misfire is intermittent or only occurs under specific conditions
  • Slightly reduced fuel economy or a faint raw-fuel smell if the misfire is frequent

Common causes, most likely first

  1. Worn or fouled spark plug on cylinder 2, including incorrect gap or a plug that has been damaged during installation
  2. Failed ignition coil or coil-on-plug boot for cylinder 2, which is a common failure on Nissan engines with individual coils
  3. Faulty fuel injector for cylinder 2, such as a clogged nozzle, internal short, or wiring issue at the injector connector
  4. Vacuum leak at the intake manifold runner or injector O-ring specific to cylinder 2, leaning out that cylinder
  5. Mechanical issue such as low compression from worn rings, a burned valve, or a failed head gasket affecting cylinder 2
  6. Engine wiring harness damage or poor ground affecting the coil or injector circuit for cylinder 2
  7. Contaminated fuel or a failing fuel pump that delivers uneven pressure to the rail, though this usually affects multiple cylinders

How to diagnose and fix it

  1. Scan all stored and pending codes with a capable OBD-II scanner and record freeze-frame data to see the conditions when P1202 set
  2. Inspect the spark plug on cylinder 2 for fouling, wear, or incorrect gap, and replace it if questionable
  3. Swap the ignition coil from cylinder 2 with a known-good coil from another cylinder and see if the misfire follows the coil
  4. Perform a cylinder balance test or use a scan tool to monitor misfire counts per cylinder while swapping injectors or coils to isolate the faulty component
  5. Check fuel injector resistance and listen for injector clicking with a stethoscope or noid light to confirm the injector is being commanded
  6. Run a compression test and, if low, a leak-down test on cylinder 2 to rule out mechanical faults before replacing ignition or fuel parts
  7. Inspect the engine wiring harness and connectors at the coil and injector for chafing, corrosion, or loose pins, and repair as needed

Why cylinder 2 misfires are often misdiagnosed

  • A P1202 code does not always mean the spark plug or coil is at fault; a leaking injector O-ring or a small vacuum leak at the intake runner for cylinder 2 can lean out that cylinder and set the same code without any ignition problem.
  • Nissan engines with variable valve timing can set a single-cylinder misfire code when the timing chain has stretched or the cam phaser is sluggish, so check for related timing codes and listen for chain rattle before replacing ignition parts.
  • Swapping components between cylinders is the fastest way to confirm a coil or injector fault, but many technicians skip this step and replace the plug and coil on cylinder 2 only to find the misfire returns because the real cause was a wiring issue or mechanical fault.
  • A misfire that only appears when the engine is cold often points to a failing injector or a valve seat issue rather than a spark plug, because plug fouling tends to worsen as the engine warms and idles.
  • The ECM may set P1202 along with a random misfire code like P0300, and the presence of P0300 does not mean the cylinder 2 fault is false; it simply means the misfire is severe enough to affect overall engine speed beyond one cylinder.

Can I keep driving with P1202?

You can usually drive a short distance to a repair shop if the check engine light is steady and the engine runs smoothly enough, but avoid hard acceleration and heavy loads. If the light is flashing or the engine shakes violently, stop driving because raw fuel can overheat and destroy the catalytic converter.

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 Nissan vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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