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P0270Cylinder 4 Injector "A" Circuit Low

What it means

The voltage on the control side of the cylinder 4 injector is lower than expected when the injector is not switched. The control wire is usually shorted to ground, so the injector may stay open.

Symptoms

  • Misfire or rough running on cylinder 4
  • Possibly a rich smell or smoke
  • Check engine light

Common causes

  • Injector control wire shorted to ground
  • Shorted injector winding
  • ECU driver fault

What to check first

  1. Measure the injector resistance
  2. Check the control wire for shorts to ground and to voltage
  3. Scope the injector to see whether the ECU switches it
Can I drive with P0270? Usually yes for a short distance, but performance or economy may suffer and the fault can get worse. Diagnose it soon.

Generic OBD-II meaning. Manufacturer-specific meanings and checks can differ; always check the service information for the car.

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P0270: questions and answers

What does P0270 mean?

P0270: Cylinder 4 Injector "A" Circuit Low. The voltage on the control side of the cylinder 4 injector is lower than expected when the injector is not switched. The control wire is usually shorted to ground, so the injector may stay open.

What are the symptoms of P0270?

Misfire or rough running on cylinder 4. Possibly a rich smell or smoke. Check engine light.

What causes P0270?

Injector control wire shorted to ground. Shorted injector winding. ECU driver fault.

How do you diagnose P0270?

1. Measure the injector resistance 2. Check the control wire for shorts to ground and to voltage 3. Scope the injector to see whether the ECU switches it

Can I drive with P0270?

Usually yes for a short distance, but performance or economy may suffer and the fault can get worse. Diagnose it soon.