Reductant Quality Sensor Performance
The system has detected a problem with the reductant quality sensor signal.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The reductant quality sensor monitors the quality of the diesel exhaust fluid (DEF). If it senses that the fluid isn’t meeting the required standards, it sends a signal to the engine control module (ECM) to indicate a problem.
What the computer is actually seeing
The ECM expects a clean and reliable signal from the reductant quality sensor, often showing values that range from 0.5V to 4.5V depending on fluid quality and temperature. Out-of-range values indicate a fault.
What a healthy reading looks like
Normal sensor output should be between 0.5V (poor quality) and 4.5V (good quality) under stable conditions.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 11. Check the DEF fluid level; it should be at least half full.
- 22. Inspect the wiring and connectors to the reductant quality sensor for damage or corrosion.
- 33. Use a scan tool to monitor real-time sensor data; check if the output voltage is between 0.5V and 4.5V.
- 44. If the sensor output is out of range, replace the reductant quality sensor and clear the codes.
- 55. If the code returns, confirm the DEF quality; it should be at least 32.5% urea.
- 66. Verify proper repairs by road testing; ensure no additional codes return.
Common causes
- Defective reductant quality sensor
- Contaminated diesel exhaust fluid
- Wiring or connector issues to the sensor
- Faulty ECM
- DEF heater problems
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's technically drivable, but emissions may be affected and further damage could occur if not addressed.
Will this code come back after clearing?
If the underlying issue isn't fixed, yes, it will return after clearing.
Can it pair with other codes?
Yes, it commonly pairs with other reductant or DEF-related codes.
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