Engine

P03A0 — Cylinder 2 Pressure Sensor Circuit Range/Performance

Severity: medium Drive with care, to a shop

What P03A0 means

P03A0 is set when the engine control module detects a signal from the cylinder 2 pressure sensor circuit that is out of range or does not match how the engine is running. These sensors, found only on some engines, measure pressure inside the combustion chamber so the ECM can judge combustion quality and adjust control. The cause can be the sensor, its wiring, or a real problem in the cylinder.

Symptoms

  • Check Engine Light on
  • Rough idle
  • Misfire on cylinder 2
  • Reduced power and sluggish acceleration
  • Poor fuel economy

Possible causes

  1. Faulty cylinder 2 pressure sensor
  2. Damaged wiring or corroded, loose connector at the sensor
  3. Open circuit or short to ground or power in the sensor circuit
  4. Cylinder 2 misfire (spark plug, ignition coil)
  5. Injector fault or low fuel pressure
  6. Internal engine problem such as low compression

How to diagnose

  1. Read all codes and freeze-frame data, and note any cylinder 2 misfire codes
  2. Inspect the sensor connector and harness for chafing, moisture, corrosion and poor latching
  3. Check power, ground and reference voltage at the sensor connector against the factory wiring diagram
  4. Test the signal wire back to the ECM for opens and shorts
  5. Watch the sensor signal live on a scan tool and compare it with other cylinders if they have sensors
  6. Inspect the cylinder 2 spark plug, coil and injector
  7. Run a compression or leak-down test on cylinder 2
  8. Clear the code and road test to see if it returns

Common fixes

  • Repair the wiring and clean or replace the connector
  • Replace the cylinder 2 pressure sensor
  • Replace the spark plug, coil or injector if it is the real cause
  • Carry out engine repair if low compression is found

Questions and answers

What does P03A0 mean?

It is a generic code meaning the cylinder 2 pressure sensor signal is out of range or implausible. The cause may be the sensor, its wiring or the cylinder itself.

Can I drive with P03A0?

If the engine runs smoothly, you can drive carefully to a shop. If it misfires or shakes, avoid driving to protect the catalytic converter and engine.

Should I replace the sensor right away?

No. Check the connector, wiring, power and ground first, and confirm cylinder 2 is mechanically sound. Replace the sensor only when everything else checks out.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.