P2046
Reductant Temperature Sensor A Circuit Intermittent
SCR / reductant (diesel emissions)
Generic OBD-II
Medium
What it means
P2046 means the signal from the reductant (diesel exhaust fluid) temperature sensor A is dropping in and out. This sensor helps the SCR system dose DEF correctly to control NOx. The engine still runs, but a persistent fault can raise emissions and, on many diesels, trigger a power derate. The usual cause is a loose connector or chafed wiring rather than the sensor itself.
Medium
Can I keep driving? Driveable short-term — the engine runs, but diesels can enter reduced power or a restart limit if the SCR fault persists, so fix it soon.
Common symptoms
What you'll notice
- Check-engine light on
- SCR / exhaust-fluid (DEF) warning message or light
- Possible reduced-power (derate) mode if the fault stays active
- Higher NOx emissions
Common causes
Most likely first
- Intermittent or corroded connection at the reductant (DEF) temperature sensorLikely
- Chafed or damaged wiring in the sensor harnessCommon
- Faulty reductant temperature sensor ACommon
- Faulty powertrain control module (rare)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and note when the fault appears (over bumps, when hot, etc.).
- Wiggle-test the sensor connector and harness to reproduce the intermittent fault.
- Inspect the wiring for chafing, heat damage, and corrosion; repair as needed.
- Check the sensor's signal with a scan tool and replace the reductant temperature sensor if it drops out.
FAQ
Quick answers
Is it safe to drive with P2046?+
For short trips, yes, but diesel emissions systems can force reduced power or limit restarts if an SCR fault stays active. Have it repaired promptly.
Can I just clear P2046?+
Because it is an intermittent fault, it will return once the loose connection or wiring acts up again. Fix the root cause instead.
Related codes
Often seen with P2046
Read & clear P2046 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX