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DTC codes / P02xx · Fuel and air metering (injector circuits) / P0202

P0202Injector Circuit Malfunction - Cylinder 2

P0202 means the engine computer has detected an electrical problem in the fuel injector circuit for cylinder number 2, such as an open circuit, short to ground, or short to power. The computer monitors the injector driver circuit and sets this code when the expected current or voltage feedback does not match what it commands.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaFuel and air metering (injector circuits)

Symptoms you may notice

  • Illuminated check engine light, often with no other noticeable symptoms
  • Rough idle or misfire that is most pronounced at idle and low engine speeds
  • Noticeable loss of power and sluggish acceleration under load
  • Shaking or vibration from the engine, especially when cold
  • Worse fuel economy than usual due to a dead or intermittently firing cylinder
  • A flashing check engine light if the misfire becomes severe enough to damage the catalytic converter

Common causes, most likely first

  1. Faulty fuel injector on cylinder 2 with an open or shorted internal coil
  2. Damaged or corroded injector harness connector at cylinder 2
  3. Broken, chafed, or pinched wire in the injector circuit between the computer and the injector
  4. Corroded or loose terminal at the engine computer connector for that injector driver
  5. Failed injector driver inside the engine control module (ECM) or powertrain control module (PCM)
  6. Aftermarket alarm or remote start wiring that has tapped into or damaged the injector circuit
  7. Rodent damage or heat-related insulation failure on the injector wiring loom

How to diagnose and fix it

  1. Scan all modules and record freeze-frame data to confirm P0202 is current and not a history code from a past repair
  2. Inspect the cylinder 2 injector connector and the visible section of its wiring for corrosion, looseness, or chafing
  3. Measure the injector coil resistance with a multimeter and compare it to the manufacturer's specification
  4. With the key on and engine off, check for battery voltage at the injector connector on the power feed side
  5. Use a noid light or oscilloscope on the injector control wire to verify the computer is pulsing the circuit
  6. Perform a resistance and voltage-drop test on the control wire from the injector back to the computer connector
  7. If the circuit tests good but the injector does not fire, replace the injector and recheck; if the circuit is faulty, repair the wiring or connector

What P0202 does not always mean

  • A P0202 does not automatically condemn the injector itself; a corroded connector or a chafed wire in the loom is just as common and far cheaper to fix.
  • The code can be set by a failed injector driver inside the computer, so replacing the injector without testing the control signal can leave the fault unchanged.
  • An injector that is mechanically clogged or dirty will usually set a misfire code rather than P0202, because the electrical circuit can still test normal.
  • Aftermarket wiring for alarms, remote starters, or audio equipment that taps into the injector harness is a frequently missed cause of this code.
  • On some engines the injector circuit shares a ground or power splice with other injectors, so a single bad splice can set codes for more than one cylinder.

Can I keep driving with P0202?

You can usually drive a short distance to a repair shop, but avoid heavy acceleration and long trips because a dead cylinder can overheat the catalytic converter. If the check engine light is flashing, stop driving and have the vehicle towed.

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 all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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