Reductant Injection System Performance
Problems detected in the reductant (DEF) injection system performance.
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 DEF system isn't working properly, which can lead to more emissions and potential engine problems.
What the computer is actually seeing
The engine control module (ECM) monitors the reductant system for performance and efficiency. It checks the reductant pump pressure, flow rate, and nozzle operation while ensuring that exhaust emissions are being treated appropriately.
What a healthy reading looks like
Reductant pump pressure should be between 30-60 psi; injector operation is expected to be within 200-400 milliseconds at the correct duty cycle.
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. Add fluid if low; normal level is above the low-level sensor.
- 22. Inspect all wiring and connectors to the DEF pump and injector. Look for corrosion or damage.
- 33. Measure the voltage at the DEF pump connector with the key on. Expected voltage is around 12V. If absent, trace wiring back to the ECM.
- 44. Connect a scan tool to monitor the reductant pump pressure. Start the engine and verify it operates in the 30-60 psi range.
- 55. If pressure is low, check for clogs in the lines or a failed pump. If normal, check the injector’s operation when activated by the ECM.
Common causes
- Faulty reductant pump
- Clogged or damaged injector
- Wiring or connector issues in the DEF circuit
- Low DEF fluid level
- Faulty DEF tank heater
Typical repair cost
$$$
Related codes
Frequently asked questions
Can I still drive with this code?
Yes, but you should fix it soon as it can lead to increased emissions and affect performance.
Will this code come back after clearing?
If the underlying issue isn't resolved, the code is likely to return shortly.
Why is this code paired with other codes?
Faults in the DEF system often affect multiple components and functions, leading to multiple related codes.
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