Reductant Quality Meter Performance
The system detects an issue with the quality of the reductant fluid (DEF).
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 computer checks if the diesel exhaust fluid (DEF) is good enough. If it's bad or contaminated, the engine won't perform correctly and can cause emissions issues.
What the computer is actually seeing
The engine control unit (ECU) monitors the DEF quality sensor's voltage signal, expecting a steady 0.5 to 4.5 volts under normal conditions. A voltage outside this range suggests poor DEF quality.
What a healthy reading looks like
Voltage from the reductant quality sensor should be between 0.5V and 4.5V while the engine is running; otherwise, it triggers the fault.
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 level in the tank. Is it adequate?
- 2 - Yes: Go to step 2. - No: Refill DEF and clear codes. Recheck after a drive cycle.
- 32. Inspect the DEF quality sensor wiring and connectors. Do you see any damage or corrosion?
- 4 - No: Go to step 3. - Yes: Repair or replace damaged wiring/connectors and clear codes.
- 53. Use a scan tool to monitor the voltage from the DEF quality sensor. Is it within 0.5V to 4.5V?
- 6 - Yes: If issues persist, consider replacing the DEF quality sensor. - No: Replace the DEF quality sensor.
- 74. If the issue is resolved, clear the code and perform a drive cycle to confirm. If not resolved, further diagnosis of the ECU and related systems is needed.
Common causes
- Contaminated or low-quality diesel exhaust fluid (DEF)
- Faulty reductant quality sensor
- Wiring issues or poor connector connections
- Low DEF level or empty DEF tank
Typical repair cost
$$ to $$$
Related codes
Frequently asked questions
Can I drive my vehicle with this code?
It's not recommended. Poor DEF quality can affect emissions and performance.
Will this issue come back after clearing the code?
If the underlying cause isn’t fixed, yes. Check DEF quality and sensor operation.
Why does it trigger with a bad DEF?
Bad DEF can lead to higher emissions and engine performance issues, which is why the system monitors its quality closely.
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