OBD Guide

P03A9

Cylinder 3 Pressure Sensor Circuit

P03A9 is an OBD-II diagnostic trouble code meaning: Cylinder 3 Pressure Sensor Circuit. Common causes: faulty cylinder 3 pressure sensor, open or short circuit in wiring harness. Estimated repair cost: $56–167.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$56–167 (est.)

Symptoms

  • Rough engine operation
  • Power reduction
  • Increased fuel consumption
  • Check Engine Light Illuminates
  • Possible misfires

Causes

  • Faulty cylinder 3 pressure sensor
  • Open or short circuit in wiring harness
  • Corroded or damaged electrical connectors
  • Problems with power or grounding of the circuit
  • ECU malfunction

How to Fix

  1. Visual inspection of the sensor wiring harness and connectors
  2. Checking resistance and continuity
  3. Measuring the sensor supply voltage
  4. Checking the sensor signal with an oscilloscope
  5. Replacing a faulty pressure sensor
  6. Cleaning connector contacts

Related codes

Error P03A9 by Vehicle Brand

FAQ

What does the P03A9 code mean?

P03A9 is an OBD-II diagnostic trouble code that indicates: Cylinder 3 Pressure Sensor Circuit

What causes a P03A9 error code?

The most common causes of P03A9 include: Faulty cylinder 3 pressure sensor; Open or short circuit in wiring harness; Corroded or damaged electrical connectors; Problems with power or grounding of the circuit.

How do I fix a P03A9 diagnostic trouble code?

To fix P03A9: Visual inspection of the sensor wiring harness and connectors. Checking resistance and continuity. Measuring the sensor supply voltage. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P03A9?

Limited driving only, diagnose soon

How much does it cost to fix P03A9?

The estimated repair cost for P03A9 is $56–167. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat