Code
P2044
Generic
P — Powertrain
Reductant Temperature Sensor A Circuit Low
Views:
UK: 18
EN: 41
RU: 24
AI status
Completed
Completed
100%
Causes
- Short to ground in sensor signal wire
- Poor or corroded connector/terminal at sensor or PCM
- Failed reductant temperature sensor (internal short or open)
- Lost reference voltage or ground at the sensor circuit
- Contaminated/soaked sensor or DEF ingress causing electrical fault
- PCM/ECM internal fault (rare)
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Reduced or inhibited SCR/aftertreatment function or limp mode on some vehicles
- Aftertreatment warnings (e.g., DEF/AdBlue system messages)
- Failed emissions inspection or failed regenerations
- Possible drivability issues if ECM limits performance
What to check
- Read freeze frame and failure records with a scan tool to confirm conditions when code set
- Check for additional related DTCs (other reductant/heater/sensor codes)
- Perform visual inspection of sensor connector, wiring harness and routing for damage, corrosion, chafing or signs of DEF contamination
- Backprobe the sensor signal, reference and ground with key on (engine off) and compare to expected values
- Measure sensor resistance (if safe and service information available) and compare to manufacturer spec vs temperature
- Wiggle wiring while monitoring live data to try to reproduce fault
Signal parameters
- Typical reductant temperature sensor signal: nominal 0.5–4.5 V (depends on vehicle and temp)
- Low-circuit threshold: often
- Reference supply typically 5 V (verify vehicle-specific value) and a good ground are required
- If sensor is thermistor type, resistance will vary with temperature — consult manufacturer table for exact ohms vs °C
Diagnostic algorithm
- Connect a scan tool, confirm P2044 and note freeze-frame/live data (sensor voltage and reductant temperature). Clear codes and attempt to re-run to confirm repeatability.
- Visually inspect sensor connector and harness from sensor to PCM for damage, corrosion, moisture or DEF crystals. Repair or replace any damaged sections.
- With connector connected, backprobe the signal, reference and ground wires. Verify reference voltage present (usually ~5 V) and good ground. If reference missing, trace back to supply/PCM.
- Check signal voltage with key ON and with sensor immersed in known-temperature fluid (if service procedure available) or compare to ambient expectations. If signal is stuck low (
- With sensor disconnected, measure continuity from signal wire to ground to check for short. Also check continuity of reference and ground circuits to PCM.
- Measure sensor resistance (disconnect sensor) and compare to manufacturer spec/temperature chart. If resistance out of spec, replace sensor.
- Perform wiggle/stress test on wiring while monitoring live data to locate intermittent opens or shorts.
- If wiring and sensor test good, suspect PCM fault. Confirm with manufacturer diagnostics before replacing PCM.
- After repairs, clear codes and verify repairs by running vehicle to operating conditions and ensuring code does not return.
Likely causes
- Wiring chafed and shorted to chassis ground near exhaust or DEF lines
- Corroded connector pins at sensor allowing low voltage reading
- Failed thermistor inside reductant temperature sensor
- Broken or disconnected 5V reference or ground circuit to the sensor
- DEF contamination causing sensor element to short or leak
Fault status
Status
Reductant Temperature Sensor A circuit voltage is below normal operating range (circuit low). Possible short to ground, missing reference/ground, or failed sensor.
Repair difficulty: Medium
Diagnostic time: 1.0-2.5 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email