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P1456

Fuel Tank Temperature Sensor Circuit.

  • Mazda
  • Powertrain
  • Manufacturer code
  • Low severity

How this code is built

P
SystemPowertrain
1
Defined byThe manufacturer
4
AreaAuxiliary emission controls
56
FaultThe specific fault in that area

What it means

On a Mazda, P1456 means the engine control unit has found a fault in the fuel tank temperature sensor circuit. The sensor signal sits outside its expected range, or is implausible compared with other temperature readings, so the control unit cannot trust the fuel tank temperature. That figure is used by the evaporative emission system monitoring.

Symptoms

  • Check engine light on
  • Evaporative system monitor will not complete, which may cause an emissions test failure
  • Usually no change in how the car drives
  • Possible difficulty with fuel level or fuel vapour related readings on some models
  • Other evaporative system codes stored alongside it

Possible causes

  • Faulty fuel tank temperature sensor, often built into the fuel pump or sender assemblylikely
  • Damaged, chafed or corroded wiring between the sensor and the control unitlikely
  • Poor connection or corrosion at the fuel pump or sender connector, or at the control unit connectorpossible
  • Short to earth or to supply voltage in the sensor signal or reference circuitpossible
  • Water or contamination ingress at the connector under the rear seat or near the tankpossible
  • Fault in the engine control unitrare

How to diagnose

  1. Read all stored and pending codes and note the freeze frame data, then check for related evaporative or fuel level codes.
  2. Check the live fuel tank temperature reading with the car cold and compare it with ambient and intake air temperature; it should be similar.
  3. Inspect the wiring and connectors at the fuel pump or sender assembly and along the harness to the control unit for damage, chafing, water or corrosion.
  4. Check the sensor circuit for open circuit, short to earth and short to voltage with the connectors disconnected, using the wiring diagram for the specific model.
  5. Measure the sensor resistance and compare it with the manufacturer's specification at a known temperature.
  6. Check the reference voltage and signal at the sensor connector with the ignition on.
  7. If the wiring and sensor are good, check the control unit connector and power and earth supplies before suspecting the control unit.

How to fix

  • Replace the fuel tank temperature sensor or the pump or sender assembly it is part of, as the model requires.
  • Repair or replace damaged wiring and terminals in the sensor circuit.
  • Clean, dry and refit the connectors, replacing any that are corroded or loose.
  • Rectify any short circuit found and replace the damaged harness section.
  • Replace or repair the control unit only after all other causes are ruled out, then clear the codes and confirm the monitor completes.

Can I keep driving?

Low severity

The car can normally be driven as usual, as this fault mainly affects evaporative emission monitoring. Book it in soon, as the warning light will stay on and an emissions test may fail.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.

This code for other makes

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