Emissions

P2054 — Reductant (DEF/AdBlue) Tank Temperature Sensor Circuit Low

Severity: medium Drive with care, to a shop

What P2054 means

The engine or SCR dosing control module reads the temperature of the DEF (AdBlue) in the tank from a sensor signal. P2054 sets when the circuit voltage is lower than expected, usually from a short to ground or a failed sensor. The module uses this temperature to decide when to heat the tank and whether dosing is allowed, so a bad reading leaves the SCR system working blind.

Symptoms

  • Check Engine light or SCR/AdBlue warning on
  • Incorrect DEF freeze warnings
  • Tank heater not working correctly
  • Possible start countdown or torque limitation on some vehicles
  • Higher NOx emissions

Possible causes

  1. Short to ground in the tank temperature sensor wiring
  2. Failed temperature sensor built into the tank module
  3. Corrosion at the tank unit connector
  4. Damaged harness or connector in the SCR circuit
  5. Faulty dosing module or reductant injector (less likely)

How to diagnose

  1. Scan for codes, save freeze frame data and check for other SCR-related DTCs
  2. Look at the tank temperature in live data: an absurdly low value points to a short
  3. Check DEF level and quality, and make sure it isn't diluted or frozen
  4. Inspect the connector and harness at the tank for corrosion, moisture and chafed insulation
  5. Unplug the sensor: if the reading goes to open circuit, suspect the sensor; if it stays low, suspect the wiring
  6. Measure sensor resistance and compare it with the manufacturer's specification
  7. Check the tank heater, dosing valve and lines
  8. Look for technical service bulletins and ECM software updates for your model

Common fixes

  • Repair the short to ground and restore the wiring
  • Clean or replace the corroded connector
  • Replace the DEF tank module with its temperature sensor
  • Replace the dosing module if it's confirmed faulty
  • Apply the ECM software update per bulletin and clear the code

Questions and answers

What does P2054 mean?

It's a low signal in the temperature sensor circuit of the SCR reductant (DEF/AdBlue) tank. The usual culprits are a short to ground or a failed tank sensor.

Can I drive with P2054?

For a short time, yes, but the exhaust treatment system may not work correctly, and some vehicles will limit power or prevent restarting. Get it diagnosed soon.

Will clearing the code fix it?

Only temporarily. If a wiring fault or sensor is the cause, the code will return, so find and repair the fault first.

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.