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DTC codes / Mazda codes / P1455

P1455 · MazdaFuel Tank Level Sensor Circuit

P1455 on Mazda vehicles indicates that the powertrain control module (PCM) has detected an abnormal signal from the fuel tank level sensor circuit, which measures how much fuel is in the tank. The PCM monitors the sensor's voltage or resistance and sets this code when the reading falls outside the expected range for the current operating conditions, often due to an open circuit, short, or faulty sensor.

SystemPowertrain
Code typeMazda specific
SeverityLow
Fix difficultyIntermediate
AreaAuxiliary emission controls

Symptoms you may notice

  • Fuel gauge reads incorrectly, such as always empty or always full
  • Fuel gauge fluctuates erratically while driving
  • Check Engine Light (CEL) illuminated on the dashboard
  • Often no symptoms besides the warning light, especially if the gauge still appears to work
  • Possible inaccurate fuel range or low-fuel warning light behavior
  • In some cases, the engine may run poorly if the PCM uses fuel level for calculations, but this is rare

Common causes, most likely first

  1. Faulty fuel tank level sensor (sending unit) inside the fuel tank
  2. Wiring damage or corrosion in the fuel level sensor circuit, including the connector at the tank
  3. Open or short circuit in the signal wire between the sensor and the PCM
  4. Poor ground connection for the fuel level sensor
  5. Failed fuel pump module assembly (if the sensor is integrated)
  6. PCM internal fault (uncommon)

How to diagnose and fix it

  1. Use a scan tool to read the fuel level sensor voltage or resistance data and compare with the actual fuel level
  2. Visually inspect the wiring and connector at the fuel tank for damage, corrosion, or loose pins
  3. Check the sensor's ground circuit for continuity to chassis ground
  4. Test the fuel level sensor resistance with a multimeter while moving the float arm through its range, comparing to Mazda specifications
  5. If the sensor is faulty, replace the fuel level sensor or fuel pump module assembly as required
  6. Repair any damaged wiring or connectors and clear the code, then verify the repair with a test drive

Fuel Gauge Quirks and Sensor Testing Tips

  • A common misdiagnosis is replacing the fuel pump when only the level sensor is faulty; on many Mazdas the sensor is available separately, so test before replacing the entire assembly.
  • The fuel level sensor circuit often shares a ground with other sensors, so a bad ground can cause multiple codes or erratic gauge behavior that mimics a sensor failure.
  • On some Mazda models, the fuel level sensor signal is used by the PCM to calculate fuel consumption and evaporative emission system readiness, so a faulty sensor can prevent certain monitors from completing.
  • Intermittent faults can be caused by a worn float arm or a dead spot in the sensor's resistive track, which may not show up in a static resistance test; a wiggle test while monitoring live data can help.
  • After repairs, the fuel gauge may need to be recalibrated or the PCM may need to relearn the fuel level; consult the factory service procedure for the specific model.

Can I keep driving with P1455?

The vehicle is generally safe to drive with this code because it primarily affects the fuel gauge accuracy, not engine operation. However, you should refuel based on mileage rather than the gauge until repaired, and avoid running the tank very low to prevent fuel starvation.

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 Mazda vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

Running on fumes Free guides aren't free to make. Top up the tank. Any amount, one time. Fuel the Garage