Reductant Injection System Performance
The reductant injection system isn't performing as expected.
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 car’s system that sprays diesel exhaust fluid (DEF) into the exhaust is not working right, which could lead to more pollution or drivability issues.
What the computer is actually seeing
The engine control module (ECM) monitors the amount of diesel exhaust fluid being injected to reduce emissions. It expects a certain amount of DEF to be injected based on your driving conditions. If it sees too little or too much fluid being injected, it sets this code.
What a healthy reading looks like
The ECM typically expects the reductant injection system to maintain an injection rate that corresponds to the engine load, around 5-10 mL/min under normal 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.
- 1Check DEF fluid level; it should be above the minimum mark and clear of contamination.
- 2Inspect wiring and connectors around the DEF injector and the ECM for any damage or corrosion.
- 3Test the voltage at the DEF injector connector; expect around 12V when activated.
- 4With a scan tool, monitor the actual DEF flow rate; it should match the expected values during operation.
Common causes
- Blocked DEF injector
- Low DEF fluid level
- DEF quality issues (contamination)
- Wiring or connector faults in the DEF system
- Faulty NOx sensor readings
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It is generally safe to drive, but emissions may be increased, and it could enter limp mode if not addressed.
Will this code come back if I clear it?
If the underlying issue is not fixed, the code will likely return as the system fails to perform as expected.
Why does this code sometimes appear with other codes?
This code often pairs with NOx sensor codes or issues with the DEF injector, indicating a systemic issue with emissions control.
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