P0399
Cylinder 1 Pressure Sensor Circuit Intermittent/Erratic
P0399 is an OBD-II diagnostic trouble code meaning: Cylinder 1 Pressure Sensor Circuit Intermittent/Erratic. Common causes: damage to the pressure sensor circuit, poor contact in the sensor connector. Estimated repair cost: $56–167.
Symptoms
- Unstable engine operation
- Misfires
- Increased fuel consumption
- Engine power drop
- Check Engine Light Is On
Causes
- Damage to the pressure sensor circuit
- Poor contact in the sensor connector
- Pressure sensor (CPS) fault
- Short circuit in wiring harness
- Problems with ECU software
How to Fix
- Check the pressure sensor circuit for opens and short circuits
- Inspect the sensor connector for oxidation or damage.
- Test the pressure sensor using a multimeter or oscilloscope
- Run ECU diagnostics for software updates
- Replace the pressure sensor if it is faulty
Related codes
Error P0399 by Vehicle Brand
FAQ
What does the P0399 code mean?
P0399 is an OBD-II diagnostic trouble code that indicates: Cylinder 1 Pressure Sensor Circuit Intermittent/Erratic
What causes a P0399 error code?
The most common causes of P0399 include: Damage to the pressure sensor circuit; Poor contact in the sensor connector; Pressure sensor (CPS) fault; Short circuit in wiring harness.
How do I fix a P0399 diagnostic trouble code?
To fix P0399: Check the pressure sensor circuit for opens and short circuits. Inspect the sensor connector for oxidation or damage.. Test the pressure sensor using a multimeter or oscilloscope. For a complete diagnosis, use an OBD-II scanner.
Is it safe to drive with P0399?
Limited driving only, diagnose soon
How much does it cost to fix P0399?
The estimated repair cost for P0399 is $56–167. Actual cost depends on your vehicle, location, and labor rates.
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